CHAPTER 3 [CE]
GENERAL REQUIREMENTS


  • SECTION C301
    CLIMATE ZONES

    C301.1 General.
    Climate zones from Figure C301.1 or Table C301.1 shall be used in determining the applicable requirements from Chapter 4. Locations not in Table C301.1 (outside the United States) shall be assigned a climate zone based on Section C301.3.

    FIGURE C301.1
    CLIMATE ZONES

    TABLE C301.1
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    Key: A – Moist, B – Dry, C – Marine. Absence of moisture designation indicates moisture regime is irrelevant.
    Asterisk (*) indicates a warm-humid location.

    US STATES
    ALABAMA3A Lee7 Kodiak Island3A Calhoun3A Monroe
    3A Autauga*3A Limestone7 Lake and Peninsula4A Carroll3A Montgomery
    2A Baldwin*3A Lowndes*7 Matanuska-Susitna3A Chicot3A Nevada
    3A Barbour*3A Macon*8 Nome3A Clark4A Newton
    3A Bibb3A Madison8 North Slope3A Clay3A Ouachita
    3A Blount3A Marengo*8 Northwest Arctic3A Cleburne3A Perry
    3A Bullock*3A Marion7 Prince of Wales3A Cleveland3A Phillips
    3A Butler*3A MarshallOuter Ketchikan3A Columbia*3A Pike
    3A Calhoun2A Mobile*7 Sitka3A Conway3A Poinsett
    3A Chambers3A Monroe*7 Skagway-Hoonah- 3A Craighead3A Polk
    3A Cherokee3A Montgomery*Angoon3A Crawford3A Pope
    3A Chilton3A Morgan8 Southeast Fairbanks3A Crittenden3A Prairie
    3A Choctaw*3A Perry*7 Valdez-Cordova3A Cross3A Pulaski
    3A Clarke*3A Pickens8 Wade Hampton3A Dallas3A Randolph
    3A Clay3A Pike*7 Wrangell-Petersburg3A Desha3A Saline
    3A Cleburne3A Randolph7 Yakutat3A Drew3A Scott
    3A Coffee*3A Russell*8 Yukon-Koyukuk3A Faulkner4A Searcy
    3A Colbert3A ShelbyARIZONA3A Franklin3A Sebastian
    3A Conecuh*3A St. Clair4A Fulton3A Sevier*
    3A Coosa3A Sumter5B Apache3A Garland3A Sharp
    3A Covington*3A Talladega3B Cochise3A Grant3A St. Francis
    3A Crenshaw*3A Tallapoosa5B Coconino3A Greene4A Stone
    3A Cullman3A Tuscaloosa4B Gila3A Hempstead*3A Union*
    3A Dale*3A Walker3B Graham3A Hot Spring3A Van Buren
    3A Dallas*3A Washington*3B Greenlee3A Howard4A Washington
    3A DeKalb3A Wilcox*2B La Paz3A Independence3A White
    3A Elmore*3A Winston2B Maricopa4A Izard3A Woodruff
    3A Escambia*ALASKA3B Mohave3A Jackson3A Yell
    3A Etowah5B Navajo3A JeffersonCALIFORNIA
    3A Fayette7 Aleutians East2B Pima3A Johnson
    3A Franklin7 Aleutians West2B Pinal3A Lafayette*3C Alameda
    3A Geneva*7 Anchorage3B Santa Cruz3A Lawrence6B Alpine
    3A Greene8 Bethel4B Yavapai3A Lee4B Amador
    3A Hale7 Bristol Bay2B Yuma3A Lincoln3B Butte
    3A Henry*7 DenaliARKANSAS3A Little River*4B Calaveras
    3A Houston*8 Dillingham3A Logan3B Colusa
    3A Jackson8 Fairbanks North Star3A Arkansas3A Lonoke3B Contra Costa
    3A Jefferson7 Haines3A Ashley4A Madison4C Del Norte
    3A Lamar7 Juneau4A Baxter4A Marion4B El Dorado
    3A Lauderdale7 Kenai Peninsula4A Benton3A Miller*3B Fresno
    3A Lawrence7 Ketchikan Gateway4A Boone3A Mississippi3B Glenn
    3A Bradley

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    4C Humboldt3B Yuba5B Morgan2A Escambia*2A Taylor*
    2B ImperialCOLORADO4B Otero2A Flagler*2A Union*
    4B Inyo6B Ouray2A Franklin*2A Volusia*
    3B Kern5B Adams7 Park2A Gadsden*2A Wakulla*
    3B Kings6B Alamosa5B Phillips2A Gilchrist*2A Walton*
    4B Lake5B Arapahoe7 Pitkin2A Glades*2A Washington*
    5B Lassen6B Archuleta5B Prowers2A Gulf*GEORGIA
    3B Los Angeles4B Baca5B Pueblo2A Hamilton*
    3B Madera5B Bent6B Rio Blanco2A Hardee*2A Appling*
    3C Marin5B Boulder7 Rio Grande2A Hendry*2A Atkinson*
    4B Mariposa6B Chaffee7 Routt2A Hernando*2A Bacon*
    3C Mendocino5B Cheyenne6B Saguache2A Highlands*2A Baker*
    3B Merced7 Clear Creek7 San Juan2A Hillsborough*3A Baldwin
    5B Modoc6B Conejos6B San Miguel2A Holmes*4A Banks
    6B Mono6B Costilla5B Sedgwick2A Indian River*3A Barrow
    3C Monterey5B Crowley7 Summit2A Jackson*3A Bartow
    3C Napa6B Custer5B Teller2A Jefferson*3A Ben Hill*
    5B Nevada5B Delta5B Washington2A Lafayette*2A Berrien*
    3B Orange5B Denver5B Weld2A Lake*3A Bibb
    3B Placer6B Dolores5B Yuma2A Lee*3A Bleckley*
    5B Plumas5B DouglasCONNECTICUT2A Leon*2A Brantley*
    3B Riverside6B Eagle2A Levy*2A Brooks*
    3B Sacramento5B Elbert5A (all)2A Liberty*2A Bryan*
    3C San Benito5B El PasoDELAWARE2A Madison*3A Bulloch*
    3B San Bernardino5B Fremont2A Manatee*3A Burke
    3B San Diego5B Garfield4A (all)2A Marion*3A Butts
    3C San Francisco5B GilpinDISTRICT OF
    COLUMBIA
    2A Martin*3A Calhoun*
    3B San Joaquin7 Grand1A Miami-Dade*2A Camden*
    3C San Luis Obispo7 Gunnison4A (all)1A Monroe*3A Candler*
    3C San Mateo7 HinsdaleFLORIDA2A Nassau*3A Carroll
    3C Santa Barbara5B Huerfano2A Okaloosa*4A Catoosa
    3C Santa Clara7 Jackson2A Alachua*2A Okeechobee*2A Charlton*
    3C Santa Cruz5B Jefferson2A Baker*2A Orange*2A Chatham*
    3B Shasta5B Kiowa2A Bay*2A Osceola*3A Chattahoochee*
    5B Sierra5B Kit Carson2A Bradford*2A Palm Beach*4A Chattooga
    5B Siskiyou7 Lake2A Brevard*2A Pasco*3A Cherokee
    3B Solano5B La Plata1A Broward*2A Pinellas*3A Clarke
    3C Sonoma5B Larimer2A Calhoun*2A Polk*3A Clay*
    3B Stanislaus4B Las Animas2A Charlotte*2A Putnam*3A Clayton
    3B Sutter5B Lincoln2A Citrus*2A Santa Rosa*2A Clinch*
    3B Tehama5B Logan2A Clay*2A Sarasota*3A Cobb
    4B Trinity5B Mesa2A Collier*2A Seminole*3A Coffee*
    3B Tulare7 Mineral2A Columbia*2A St. Johns*2A Colquitt*
    4B Tuolumne6B Moffat2A DeSoto*2A St. Lucie*3A Columbia
    3C Ventura5B Montezuma2A Dixie*2A Sumter*2A Cook*
    3B Yolo5B Montrose2A Duval*2A Suwannee*3A Coweta

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    3A Crawford2A Lanier*3A Taylor*5B Cassia4A Crawford
    3A Crisp*3A Laurens*3A Telfair*6B Clark5A Cumberland
    4A Dade3A Lee*3A Terrell*5B Clearwater5A DeKalb
    4A Dawson2A Liberty*2A Thomas*6B Custer5A De Witt
    2A Decatur*3A Lincoln3A Tift*5B Elmore5A Douglas
    3A DeKalb2A Long*2A Toombs*6B Franklin5A DuPage
    3A Dodge*2A Lowndes*4A Towns6B Fremont5A Edgar
    3A Dooly*4A Lumpkin3A Treutlen*5B Gem4A Edwards
    3A Dougherty*3A Macon*3A Troup5B Gooding4A Effingham
    3A Douglas3A Madison3A Turner*5B Idaho4A Fayette
    3A Early*3A Marion*3A Twiggs*6B Jefferson5A Ford
    2A Echols*3A McDuffie4A Union5B Jerome4A Franklin
    2A Effingham*2A McIntosh*3A Upson5B Kootenai5A Fulton
    3A Elbert3A Meriwether4A Walker5B Latah4A Gallatin
    3A Emanuel*2A Miller*3A Walton6B Lemhi5A Greene
    2A Evans*2A Mitchell*2A Ware*5B Lewis5A Grundy
    4A Fannin3A Monroe3A Warren5B Lincoln4A Hamilton
    3A Fayette3A Montgomery*3A Washington6B Madison5A Hancock
    4A Floyd3A Morgan2A Wayne*5B Minidoka4A Hardin
    3A Forsyth4A Murray3A Webster*5B Nez Perce5A Henderson
    4A Franklin3A Muscogee3A Wheeler*6B Oneida5A Henry
    3A Fulton3A Newton4A White5B Owyhee5A Iroquois
    4A Gilmer3A Oconee4A Whitfield5B Payette4A Jackson
    3A Glascock3A Oglethorpe3A Wilcox*5B Power4A Jasper
    2A Glynn*3A Paulding3A Wilkes5B Shoshone4A Jefferson
    4A Gordon3A Peach*3A Wilkinson6B Teton5A Jersey
    2A Grady*4A Pickens3A Worth*5B Twin Falls5A Jo Daviess
    3A Greene2A Pierce*HAWAII6B Valley4A Johnson
    3A Gwinnett3A Pike5B Washington5A Kane
    4A Habersham3A Polk1A (all)*ILLINOIS5A Kankakee
    4A Hall3A Pulaski*IDAHO5A Kendall
    3A Hancock3A Putnam5A Adams5A Knox
    3A Haralson3A Quitman*5B Ada4A Alexander5A Lake
    3A Harris4A Rabun6B Adams4A Bond5A La Salle
    3A Hart3A Randolph*6B Bannock5A Boone4A Lawrence
    3A Heard3A Richmond6B Bear Lake5A Brown5A Lee
    3A Henry3A Rockdale5B Benewah5A Bureau5A Livingston
    3A Houston*3A Schley*6B Bingham5A Calhoun5A Logan
    3A Irwin*3A Screven*6B Blaine5A Carroll5A Macon
    3A Jackson2A Seminole*6B Boise5A Cass4A Macoupin
    3A Jasper3A Spalding6B Bonner5A Champaign4A Madison
    2A Jeff Davis*4A Stephens6B Bonneville4A Christian4A Marion
    3A Jefferson3A Stewart*6B Boundary5A Clark5A Marshall
    3A Jenkins*3A Sumter*6B Butte4A Clay5A Mason
    3A Johnson*3A Talbot6B Camas4A Clinton4A Massac
    3A Jones3A Taliaferro5B Canyon5A Coles5A McDonough
    3A Lamar2A Tattnall*6B Caribou5A Cook5A McHenry

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    5A McLean5A Boone5A Miami5A Appanoose5A Jasper
    5A Menard4A Brown4A Monroe5A Audubon5A Jefferson
    5A Mercer5A Carroll5A Montgomery5A Benton5A Johnson
    4A Monroe5A Cass5A Morgan6A Black Hawk5A Jones
    4A Montgomery4A Clark5A Newton5A Boone5A Keokuk
    5A Morgan5A Clay5A Noble6A Bremer6A Kossuth
    5A Moultrie5A Clinton4A Ohio6A Buchanan5A Lee
    5A Ogle4A Crawford4A Orange6A Buena Vista5A Linn
    5A Peoria4A Daviess5A Owen6A Butler5A Louisa
    4A Perry4A Dearborn5A Parke6A Calhoun5A Lucas
    5A Piatt5A Decatur4A Perry5A Carroll6A Lyon
    5A Pike5A De Kalb4A Pike5A Cass5A Madison
    4A Pope5A Delaware5A Porter5A Cedar5A Mahaska
    4A Pulaski4A Dubois4A Posey6A Cerro Gordo5A Marion
    5A Putnam5A Elkhart5A Pulaski6A Cherokee5A Marshall
    4A Randolph5A Fayette5A Putnam6A Chickasaw5A Mills
    4A Richland4A Floyd5A Randolph5A Clarke6A Mitchell
    5A Rock Island5A Fountain4A Ripley6A Clay5A Monona
    4A Saline5A Franklin5A Rush6A Clayton5A Monroe
    5A Sangamon5A Fulton4A Scott5A Clinton5A Montgomery
    5A Schuyler4A Gibson5A Shelby5A Crawford5A Muscatine
    5A Scott5A Grant4A Spencer5A Dallas6A O’Brien
    4A Shelby4A Greene5A Starke5A Davis6A Osceola
    5A Stark5A Hamilton5A Steuben5A Decatur5A Page
    4A St. Clair5A Hancock5A St. Joseph6A Delaware6A Palo Alto
    5A Stephenson4A Harrison4A Sullivan5A Des Moines6A Plymouth
    5A Tazewell5A Hendricks4A Switzerland6A Dickinson6A Pocahontas
    4A Union5A Henry5A Tippecanoe5A Dubuque5A Polk
    5A Vermilion5A Howard5A Tipton6A Emmet5A Pottawattamie
    4A Wabash5A Huntington5A Union6A Fayette5A Poweshiek
    5A Warren4A Jackson4A Vanderburgh6A Floyd5A Ringgold
    4A Washington5A Jasper5A Vermillion6A Franklin6A Sac
    4A Wayne5A Jay5A Vigo5A Fremont5A Scott
    4A White4A Jefferson5A Wabash5A Greene5A Shelby
    5A Whiteside4A Jennings5A Warren6A Grundy6A Sioux
    5A Will5A Johnson4A Warrick5A Guthrie5A Story
    4A Williamson4A Knox4A Washington6A Hamilton5A Tama
    5A Winnebago5A Kosciusko5A Wayne6A Hancock5A Taylor
    5A Woodford5A Lagrange5A Wells6A Hardin5A Union
    INDIANA5A Lake5A White5A Harrison5A Van Buren
    5A La Porte5A Whitley5A Henry5A Wapello
    5A Adams4A LawrenceIOWA6A Howard5A Warren
    5A Allen5A Madison6A Humboldt5A Washington
    5A Bartholomew5A Marion5A Adair6A Ida5A Wayne
    5A Benton5A Marshall5A Adams5A Iowa6A Webster
    5A Blackford4A Martin6A Allamakee5A Jackson6A Winnebago

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    6A Winneshiek4A Haskell4A Sedgwick2A Iberville*6A Cumberland
    5A Woodbury4A Hodgeman4A Seward3A Jackson*6A Franklin
    6A Worth4A Jackson4A Shawnee2A Jefferson*6A Hancock
    6A Wright4A Jefferson5A Sheridan2A Jefferson Davis*6A Kennebec
    KANSAS5A Jewell5A Sherman2A Lafayette*6A Knox
    4A Johnson5A Smith2A Lafourche*6A Lincoln
    4A Allen4A Kearny4A Stafford3A La Salle*6A Oxford
    4A Anderson4A Kingman4A Stanton3A Lincoln*6A Penobscot
    4A Atchison4A Kiowa4A Stevens2A Livingston*6A Piscataquis
    4A Barber4A Labette4A Sumner3A Madison*6A Sagadahoc
    4A Barton5A Lane5A Thomas3A Morehouse6A Somerset
    4A Bourbon4A Leavenworth5A Trego3A Natchitoches*6A Waldo
    4A Brown4A Lincoln4A Wabaunsee2A Orleans*6A Washington
    4A Butler4A Linn5A Wallace3A Ouachita*6A York
    4A Chase5A Logan4A Washington2A Plaquemines*MARYLAND
    4A Chautauqua4A Lyon5A Wichita2A Pointe Coupee*
    4A Cherokee4A Marion4A Wilson2A Rapides*4A Allegany
    5A Cheyenne4A Marshall4A Woodson3A Red River*4A Anne Arundel
    4A Clark4A McPherson4A Wyandotte3A Richland*4A Baltimore
    4A Clay4A MeadeKENTUCKY3A Sabine*4A Baltimore (city)
    5A Cloud4A Miami2A St. Bernard*4A Calvert
    4A Coffey5A Mitchell4A (all)2A St. Charles*4A Caroline
    4A Comanche4A MontgomeryLOUISIANA2A St. Helena*4A Carroll
    4A Cowley4A Morris2A St. James*4A Cecil
    4A Crawford4A Morton2A Acadia*2A St. John4A Charles
    5A Decatur4A Nemaha2A Allen*the Baptist*4A Dorchester
    4A Dickinson4A Neosho2A Ascension*2A St. Landry*4A Frederick
    4A Doniphan5A Ness2A Assumption*2A St. Martin*5A Garrett
    4A Douglas5A Norton2A Avoyelles*2A St. Mary*4A Harford
    4A Edwards4A Osage2A Beauregard*2A St. Tammany*4A Howard
    4A Elk5A Osborne3A Bienville*2A Tangipahoa*4A Kent
    5A Ellis4A Ottawa3A Bossier*3A Tensas*4A Montgomery
    4A Ellsworth4A Pawnee3A Caddo*2A Terrebonne*4A Prince George’s
    4A Finney5A Phillips2A Calcasieu*3A Union*4A Queen Anne’s
    4A Ford4A Pottawatomie3A Caldwell*2A Vermilion*4A Somerset
    4A Franklin4A Pratt2A Cameron*3A Vernon*4A St. Mary’s
    4A Geary5A Rawlins3A Catahoula*2A Washington*4A Talbot
    5A Gove4A Reno3A Claiborne*3A Webster*4A Washington
    5A Graham5A Republic3A Concordia*2A West Baton4A Wicomico
    4A Grant4A Rice3A De Soto*Rouge*4A Worcester
    4A Gray4A Riley2A East Baton Rouge*3A West CarrollMASSACHSETTS
    5A Greeley5A Rooks3A East Carroll2A West Feliciana*
    4A Greenwood4A Rush2A East Feliciana*3A Winn*5A (all)
    5A Hamilton4A Russell2A Evangeline*MAINEMICHIGAN
    4A Harper4A Saline3A Franklin*
    4A Harvey5A Scott3A Grant*6A Androscoggin6A Alcona
    2A Iberia*7 Aroostook6A Alger

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    5A Allegan7 Mackinac6A Carver7 Otter Tail3A Clarke
    6A Alpena5A Macomb7 Cass7 Pennington3A Clay
    6A Antrim6A Manistee6A Chippewa7 Pine3A Coahoma
    6A Arenac6A Marquette6A Chisago6A Pipestone3A Copiah*
    7 Baraga6A Mason7 Clay7 Polk3A Covington*
    5A Barry6A Mecosta7 Clearwater6A Pope3A DeSoto
    5A Bay6A Menominee7 Cook6A Ramsey3A Forrest*
    6A Benzie5A Midland6A Cottonwood7 Red Lake3A Franklin*
    5A Berrien6A Missaukee7 Crow Wing6A Redwood3A George*
    5A Branch5A Monroe6A Dakota6A Renville3A Greene*
    5A Calhoun5A Montcalm6A Dodge6A Rice3A Grenada
    5A Cass6A Montmorency6A Douglas6A Rock2A Hancock*
    6A Charlevoix5A Muskegon6A Faribault7 Roseau2A Harrison*
    6A Cheboygan6A Newaygo6A Fillmore6A Scott3A Hinds*
    7 Chippewa5A Oakland6A Freeborn6A Sherburne3A Holmes
    6A Clare6A Oceana6A Goodhue6A Sibley3A Humphreys
    5A Clinton6A Ogemaw7 Grant6A Stearns3A Issaquena
    6A Crawford7 Ontonagon6A Hennepin6A Steele3A Itawamba
    6A Delta6A Osceola6A Houston6A Stevens2A Jackson*
    6A Dickinson6A Oscoda7 Hubbard7St. Louis3A Jasper
    5A Eaton6A Otsego6A Isanti6A Swift3A Jefferson*
    6A Emmet5A Ottawa7 Itasca6A Todd3A Jefferson Davis*
    5A Genesee6A Presque Isle6A Jackson6A Traverse3A Jones*
    6A Gladwin6A Roscommon7 Kanabec6A Wabasha3A Kemper
    7 Gogebic5A Saginaw6A Kandiyohi7 Wadena3A Lafayette
    6A Grand Traverse6A Sanilac7 Kittson6A Waseca3A Lamar*
    5A Gratiot7 Schoolcraft7 Koochiching6A Washington3A Lauderdale
    5A Hillsdale5A Shiawassee6A Lac qui Parle6A Watonwan3A Lawrence*
    7 Houghton5A St. Clair7 Lake7 Wilkin3A Leake
    6A Huron5A St. Joseph7 Lake of the Woods6A Winona3A Lee
    5A Ingham5A Tuscola6A Le Sueur6A Wright3A Leflore
    5A Ionia5A Van Buren6A Lincoln6A Yellow3A Lincoln*
    6A Iosco5A Washtenaw6A LyonMedicine3A Lowndes
    7 Iron5A Wayne7 MahnomenMISSISSIPPI3A Madison
    6A Isabella6A Wexford7 Marshall3A Marion*
    5A JacksonMINNESOTA6A Martin3A Adams*3A Marshall
    5A Kalamazoo6A McLeod3A Alcorn3A Monroe
    6A Kalkaska7 Aitkin6A Meeker3A Amite*3A Montgomery
    5A Kent6A Anoka7 Mille Lacs3A Attala3A Neshoba
    7 Keweenaw7 Becker6A Morrison3A Benton3A Newton
    6A Lake7 Beltrami6A Mower3A Bolivar3A Noxubee
    5A Lapeer6A Benton6A Murray3A Calhoun3A Oktibbeha
    6A Leelanau6A Big Stone6A Nicollet3A Carroll3A Panola
    5A Lenawee6A Blue Earth6A Nobles3A Chickasaw2A Pearl River*
    5A Livingston6A Brown7 Norman3A Choctaw3A Perry*
    7 Luce7 Carlton6A Olmsted3A Claiborne*3A Pike*

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    3A Pontotoc5A Chariton4A Mississippi4A Webster4A Cumberland
    3A Prentiss4A Christian4A Moniteau5A Worth4A Essex
    3A Quitman5A Clark4A Monroe4A Wright4A Gloucester
    3A Rankin*4A Clay4A MontgomeryMONTANA4A Hudson
    3A Scott5A Clinton4A Morgan5A Hunterdon
    3A Sharkey4A Cole4A New Madrid6B (all)5A Mercer
    3A Simpson*4A Cooper4A NewtonNEBRASKA4A Middlesex
    3A Smith*4A Crawford5A Nodaway4A Monmouth
    2A Stone*4A Dade4A Oregon5A (all)5A Morris
    3A Sunflower4A Dallas4A OsageNEVADA4A Ocean
    3A Tallahatchie5A Daviess4A Ozark5A Passaic
    3A Tate5A DeKalb4A Pemiscot5B Carson City (city)4A Salem
    3A Tippah4A Dent4A Perry5B Churchill5A Somerset
    3A Tishomingo4A Douglas4A Pettis3B Clark5A Sussex
    3A Tunica4A Dunklin4A Phelps5B Douglas4A Union
    3A Union4A Franklin5A Pike5B Elko5A Warren
    3A Walthall*4A Gasconade4A Platte5B EsmeraldaNEW MEXICO
    3A Warren*5A Gentry4A Polk5B Eureka
    3A Washington4A Greene4A Pulaski5B Humboldt4B Bernalillo
    3A Wayne*5A Grundy5A Putnam5B Lander5B Catron
    3A Webster5A Harrison5A Ralls5B Lincoln3B Chaves
    3A Wilkinson*4A Henry4A Randolph5B Lyon4B Cibola
    3A Winston4A Hickory4A Ray5B Mineral5B Colfax
    3A Yalobusha5A Holt4A Reynolds5B Nye4B Curry
    3A Yazoo4A Howard4A Ripley5B Pershing4B DeBaca
    MISSOURI4A Howell4A Saline5B Storey3B Dona Ana
    4A Iron5A Schuyler5B Washoe3B Eddy
    5A Adair4A Jackson5A Scotland5B White Pine4B Grant
    5A Andrew4A Jasper4A ScottNEW
    HAMPSHIRE
    4B Guadalupe
    5A Atchison4A Jefferson4A Shannon5B Harding
    4A Audrain4A Johnson5A Shelby6A Belknap3B Hidalgo
    4A Barry5A Knox4A St. Charles6A Carroll3B Lea
    4A Barton4A Laclede4A St. Clair5A Cheshire4B Lincoln
    4A Bates4A Lafayette4A Ste. Genevieve6A Coos5B Los Alamos
    4A Benton4A Lawrence4A St. Francois6A Grafton3B Luna
    4A Bollinger5A Lewis4A St. Louis5A Hillsborough5B McKinley
    4A Boone4A Lincoln4A St. Louis (city)6A Merrimack5B Mora
    5A Buchanan5A Linn4A Stoddard5A Rockingham3B Otero
    4A Butler5A Livingston4A Stone5A Strafford4B Quay
    5A Caldwell5A Macon5A Sullivan6A Sullivan5B Rio Arriba
    4A Callaway4A Madison4A TaneyNEW JERSEY4B Roosevelt
    4A Camden4A Maries4A Texas5B Sandoval
    4A Cape Girardeau5A Marion4A Vernon4A Atlantic5B San Juan
    4A Carroll4A McDonald4A Warren5A Bergen5B San Miguel
    4A Carter5A Mercer4A Washington4A Burlington5B Santa Fe
    4A Cass4A Miller4A Wayne4A Camden4B Sierra
    4A Cedar4A Cape May4B Socorro

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    5B Taos4A Queens4A Clay4A Orange7 Divide
    5B Torrance5A Rensselaer4A Cleveland3A Pamlico6A Dunn
    4B Union4A Richmond3A Columbus*3A Pasquotank7 Eddy
    4B Valencia5A Rockland3A Craven3A Pender*6A Emmons
    NEW YORK5A Saratoga3A Cumberland3A Perquimans7 Foster
    5A Schenectady3A Currituck4A Person6A Golden Valley
    5A Albany6A Schoharie3A Dare3A Pitt7 Grand Forks
    6A Allegany6A Schuyler3A Davidson4A Polk6A Grant
    4A Bronx5A Seneca4A Davie3A Randolph7 Griggs
    6A Broome6A Steuben3A Duplin3A Richmond6A Hettinger
    6A Cattaraugus6A St. Lawrence4A Durham3A Robeson7 Kidder
    5A Cayuga4A Suffolk3A Edgecombe4A Rockingham6A LaMoure
    5A Chautauqua6A Sullivan4A Forsyth3A Rowan6A Logan
    5A Chemung5A Tioga4A Franklin4A Rutherford7 McHenry
    6A Chenango6A Tompkins3A Gaston3A Sampson6A McIntosh
    6A Clinton6A Ulster4A Gates3A Scotland6A McKenzie
    5A Columbia6A Warren4A Graham3A Stanly7 McLean
    5A Cortland5A Washington4A Granville4A Stokes6A Mercer
    6A Delaware5A Wayne3A Greene4A Surry6A Morton
    5A Dutchess4A Westchester4A Guilford4A Swain7 Mountrail
    5A Erie6A Wyoming4A Halifax4A Transylvania7 Nelson
    6A Essex5A Yates4A Harnett3A Tyrrell6A Oliver
    6A FranklinNORTH
    CAROLINA
    4A Haywood3A Union7 Pembina
    6A Fulton4A Henderson4A Vance7 Pierce
    5A Genesee4A Hertford4A Wake7 Ramsey
    5A Greene4A Alamance3A Hoke4A Warren6A Ransom
    6A Hamilton4A Alexander3A Hyde3A Washington7 Renville
    6A Herkimer5A Alleghany4A Iredell5A Watauga6A Richland
    6A Jefferson3A Anson4A Jackson3A Wayne7 Rolette
    4A Kings5A Ashe3A Johnston4A Wilkes6A Sargent
    6A Lewis5A Avery3A Jones3A Wilson7 Sheridan
    5A Livingston3A Beaufort4A Lee4A Yadkin6A Sioux
    6A Madison4A Bertie3A Lenoir5A Yancey6A Slope
    5A Monroe3A Bladen4A LincolnNORTH DAKOTA6A Stark
    6A Montgomery3A Brunswick*4A Macon7 Steele
    4A Nassau4A Buncombe4A Madison6A Adams7 Stutsman
    4A New York4A Burke3A Martin7 Barnes7 Towner
    5A Niagara3A Cabarrus4A McDowell7 Benson7 Traill
    6A Oneida4A Caldwell3A Mecklenburg6A Billings7 Walsh
    5A Onondaga3A Camden5A Mitchell7 Bottineau7 Ward
    5A Ontario3A Carteret*3A Montgomery6A Bowman7 Wells
    5A Orange4A Caswell3A Moore7 Burke7 Williams
    5A Orleans4A Catawba4A Nash6A BurleighOHIO
    5A Oswego4A Chatham3A New Hanover*7 Cass
    6A Otsego4A Cherokee4A Northampton7 Cavalier4A Adams
    5A Putnam3A Chowan3A Onslow*6A Dickey5A Allen

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    5A Ashland5A Mahoning3A Bryan3A Okfuskee4C Linn
    5A Ashtabula5A Marion3A Caddo3A Oklahoma5B Malheur
    5A Athens5A Medina3A Canadian3A Okmulgee4C Marion
    5A Auglaize5A Meigs3A Carter3A Osage5B Morrow
    5A Belmont5A Mercer3A Cherokee3A Ottawa4C Multnomah
    4A Brown5A Miami3A Choctaw3A Pawnee4C Polk
    5A Butler5A Monroe4B Cimarron3A Payne5B Sherman
    5A Carroll5A Montgomery3A Cleveland3A Pittsburg4C Tillamook
    5A Champaign5A Morgan3A Coal3A Pontotoc5B Umatilla
    5A Clark5A Morrow3A Comanche3A Pottawatomie5B Union
    4A Clermont5A Muskingum3A Cotton3A Pushmataha5B Wallowa
    5A Clinton5A Noble3A Craig3A Roger Mills5B Wasco
    5A Columbiana5A Ottawa3A Creek3A Rogers4C Washington
    5A Coshocton5A Paulding3A Custer3A Seminole5B Wheeler
    5A Crawford5A Perry3A Delaware3A Sequoyah4C Yamhill
    5A Cuyahoga5A Pickaway3A Dewey3A StephensPENNSYLVANIA
    5A Darke4A Pike3A Ellis4B Texas
    5A Defiance5A Portage3A Garfield3A Tillman5A Adams
    5A Delaware5A Preble3A Garvin3A Tulsa5A Allegheny
    5A Erie5A Putnam3A Grady3A Wagoner5A Armstrong
    5A Fairfield5A Richland3A Grant3A Washington5A Beaver
    5A Fayette5A Ross3A Greer3A Washita5A Bedford
    5A Franklin5A Sandusky3A Harmon3A Woods5A Berks
    5A Fulton4A Scioto3A Harper3A Woodward5A Blair
    4A Gallia5A Seneca3A HaskellOREGON5A Bradford
    5A Geauga5A Shelby3A Hughes4A Bucks
    5A Greene5A Stark3A Jackson5B Baker5A Butler
    5A Guernsey5A Summit3A Jefferson4C Benton5A Cambria
    4A Hamilton5A Trumbull3A Johnston4C Clackamas6A Cameron
    5A Hancock5A Tuscarawas3A Kay4C Clatsop5A Carbon
    5A Hardin5A Union3A Kingfisher4C Columbia5A Centre
    5A Harrison5A Van Wert3A Kiowa4C Coos4A Chester
    5A Henry5A Vinton3A Latimer5B Crook5A Clarion
    5A Highland5A Warren3A Le Flore4C Curry6A Clearfield
    5A Hocking4A Washington3A Lincoln5B Deschutes5A Clinton
    5A Holmes5A Wayne3A Logan4C Douglas5A Columbia
    5A Huron5A Williams3A Love5B Gilliam5A Crawford
    5A Jackson5A Wood3A Major5B Grant5A Cumberland
    5A Jefferson5A Wyandot3A Marshall5B Harney5A Dauphin
    5A KnoxOKLAHOMA3A Mayes5B Hood River4A Delaware
    5A Lake3A McClain4C Jackson6A Elk
    4A Lawrence3A Adair3A McCurtain5B Jefferson5A Erie
    5A Licking3A Alfalfa3A McIntosh4C Josephine5A Fayette
    5A Logan3A Atoka3A Murray5B Klamath5A Forest
    5A Lorain4B Beaver3A Muskogee5B Lake5A Franklin
    5A Lucas3A Beckham3A Noble4C Lane5A Fulton
    5A Madison3A Blaine3A Nowata4C Lincoln5A Greene

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    5A Huntingdon3A Bamberg*5A Bennett6A Minnehaha4A Gibson
    5A Indiana3A Barnwell*5A Bon Homme6A Moody4A Giles
    5A Jefferson3A Beaufort*6A Brookings6A Pennington4A Grainger
    5A Juniata3A Berkeley*6A Brown6A Perkins4A Greene
    5A Lackawanna3A Calhoun6A Brule6A Potter4A Grundy
    5A Lancaster3A Charleston*6A Buffalo6A Roberts4A Hamblen
    5A Lawrence3A Cherokee6A Butte6A Sanborn4A Hamilton
    5A Lebanon3A Chester6A Campbell6A Shannon4A Hancock
    5A Lehigh3A Chesterfield5A Charles Mix6A Spink3A Hardeman
    5A Luzerne3A Clarendon6A Clark6A Stanley3A Hardin
    5A Lycoming3A Colleton*5A Clay6A Sully4A Hawkins
    6A McKean3A Darlington6A Codington5A Todd3A Haywood
    5A Mercer3A Dillon6A Corson5A Tripp3A Henderson
    5A Mifflin3A Dorchester*6A Custer6A Turner4A Henry
    5A Monroe3A Edgefield6A Davison5A Union4A Hickman
    4A Montgomery3A Fairfield6A Day6A Walworth4A Houston
    5A Montour3A Florence6A Deuel5A Yankton4A Humphreys
    5A Northampton3A Georgetown*6A Dewey6A Ziebach4A Jackson
    5A Northumberland3A Greenville5A DouglasTENNESSEE4A Jefferson
    5A Perry3A Greenwood6A Edmunds4A Johnson
    4A Philadelphia3A Hampton*6A Fall River4A Anderson4A Knox
    5A Pike3A Horry*6A Faulk4A Bedford3A Lake
    6A Potter3A Jasper*6A Grant4A Benton3A Lauderdale
    5A Schuylkill3A Kershaw5A Gregory4A Bledsoe4A Lawrence
    5A Snyder3A Lancaster6A Haakon4A Blount4A Lewis
    5A Somerset3A Laurens6A Hamlin4A Bradley4A Lincoln
    5A Sullivan3A Lee6A Hand4A Campbell4A Loudon
    6A Susquehanna3A Lexington6A Hanson4A Cannon4A Macon
    6A Tioga3A Marion6A Harding4A Carroll3A Madison
    5A Union3A Marlboro6A Hughes4A Carter4A Marion
    5A Venango3A McCormick5A Hutchinson4A Cheatham4A Marshall
    5A Warren3A Newberry6A Hyde3A Chester4A Maury
    5A Washington3A Oconee5A Jackson4A Claiborne4A McMinn
    6A Wayne3A Orangeburg6A Jerauld4A Clay3A McNairy
    5A Westmoreland3A Pickens6A Jones4A Cocke4A Meigs
    5A Wyoming3A Richland6A Kingsbury4A Coffee4A Monroe
    4A York3A Saluda6A Lake3A Crockett4A Montgomery
    RHODE ISLAND3A Spartanburg6A Lawrence4A Cumberland4A Moore
    3A Sumter6A Lincoln4A Davidson4A Morgan
    5A (all)3A Union6A Lyman4A Decatur4A Obion
    SOUTH
    CAROLINA
    3A Williamsburg6A Marshall4A DeKalb4A Overton
    3A York6A McCook4A Dickson4A Perry
    3A AbbevilleSOUTH DAKOTA6A McPherson3A Dyer4A Pickett
    3A Aiken6A Meade3A Fayette4A Polk
    3A Allendale*6A Aurora5A Mellette4A Fentress4A Putnam
    3A Anderson6A Beadle6A Miner4A Franklin4A Rhea

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    4A Roane3B Brewster3B Ector3B Howard3B McCulloch
    4A Robertson4B Briscoe2B Edwards*3B Hudspeth2A McLennan*
    4A Rutherford2A Brooks*3A Ellis*3A Hunt*2A McMullen*
    4A Scott3A Brown*3B El Paso4B Hutchinson2B Medina*
    4A Sequatchie2A Burleson*3A Erath*3B Irion3B Menard
    4A Sevier3A Burnet*2A Falls*3A Jack3B Midland
    3A Shelby2A Caldwell*3A Fannin2A Jackson*2A Milam*
    4A Smith2A Calhoun*2A Fayette*2A Jasper*3A Mills*
    4A Stewart3B Callahan3B Fisher3B Jeff Davis3B Mitchell
    4A Sullivan2A Cameron*4B Floyd2A Jefferson*3A Montague
    4A Sumner3A Camp*3B Foard2A Jim Hogg*2A Montgomery*
    3A Tipton4B Carson2A Fort Bend*2A Jim Wells*4B Moore
    4A Trousdale3A Cass*3A Franklin*3A Johnson*3A Morris*
    4A Unicoi4B Castro2A Freestone*3B Jones3B Motley
    4A Union2A Chambers*2B Frio*2A Karnes*3A Nacogdoches*
    4A Van Buren2A Cherokee*3B Gaines3A Kaufman*3A Navarro*
    4A Warren3B Childress2A Galveston*3A Kendall*2A Newton*
    4A Washington3A Clay3B Garza2A Kenedy*3B Nolan
    4A Wayne4B Cochran3A Gillespie*3B Kent2A Nueces*
    4A Weakley3B Coke3B Glasscock3B Kerr4B Ochiltree
    4A White3B Coleman2A Goliad*3B Kimble4B Oldham
    4A Williamson3A Collin*2A Gonzales*3B King2A Orange*
    4A Wilson3B Collingsworth4B Gray2B Kinney*3A Palo Pinto*
    TEXAS2A Colorado*3A Grayson2A Kleberg*3A Panola*
    2A Comal*3A Gregg*3B Knox3A Parker*
    2A Anderson*3A Comanche*2A Grimes*3A Lamar*4B Parmer
    3B Andrews3B Concho2A Guadalupe*4B Lamb3B Pecos
    2A Angelina*3A Cooke4B Hale3A Lampasas*2A Polk*
    2A Aransas*2A Coryell*3B Hall2B La Salle*4B Potter
    3A Archer3B Cottle3A Hamilton*2A Lavaca*3B Presidio
    4B Armstrong3B Crane4B Hansford2A Lee*3A Rains*
    2A Atascosa*3B Crockett3B Hardeman2A Leon*4B Randall
    2A Austin*3B Crosby2A Hardin*2A Liberty*3B Reagan
    4B Bailey3B Culberson2A Harris*2A Limestone*2B Real*
    2B Bandera*4B Dallam3A Harrison*4B Lipscomb3A Red River*
    2A Bastrop*3A Dallas*4B Hartley2A Live Oak*3B Reeves
    3B Baylor3B Dawson3B Haskell3A Llano*2A Refugio*
    2A Bee*4B Deaf Smith2A Hays*3B Loving4B Roberts
    2A Bell*3A Delta3B Hemphill3B Lubbock2A Robertson*
    2A Bexar*3A Denton*3A Henderson*3B Lynn3A Rockwall*
    3A Blanco*2A DeWitt*2A Hidalgo*2A Madison*3B Runnels
    3B Borden3B Dickens2A Hill*3A Marion*3A Rusk*
    2A Bosque*2B Dimmit*4B Hockley3B Martin3A Sabine*
    3A Bowie*4B Donley3A Hood*3B Mason3A San Augustine*
    2A Brazoria*2A Duval*3A Hopkins*2A Matagorda*2A San Jacinto*
    2A Brazos*3A Eastland2A Houston*2B Maverick*2A San Patricio*

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    3A San Saba*3A Young4C Clark4A GilmerWISCONSIN
    3B Schleicher2B Zapata*5B Columbia5A Grant6A Adams
    3B Scurry2B Zavala*4C Cowlitz5A Greenbrier7 Ashland
    3B ShackelfordUTAH5B Douglas5A Hampshire6A Barron
    3A Shelby*6B Ferry5A Hancock7 Bayfield
    4B Sherman5B Beaver5B Franklin5A Hardy6A Brown
    3A Smith*6B Box Elder5B Garfield5A Harrison6A Buffalo
    3A Somervell*6B Cache5B Grant4A Jackson7 Burnett
    2A Starr*6B Carbon4C Grays Harbor4A Jefferson6A Calumet
    3A Stephens6B Daggett4C Island4A Kanawha6A Chippewa
    3B Sterling5B Davis4C Jefferson5A Lewis6A Clark
    3B Stonewall6B Duchesne4C King4A Lincoln6A Columbia
    3B Sutton5B Emery4C Kitsap4A Logan6A Crawford
    4B Swisher5B Garfield5B Kittitas5A Marion6A Dane
    3A Tarrant*5B Grand5B Klickitat5A Marshall6A Dodge
    3B Taylor5B Iron4C Lewis4A Mason6A Door
    3B Terrell5B Juab5B Lincoln4A McDowell7 Douglas
    3B Terry5B Kane4C Mason4A Mercer6A Dunn
    3B Throckmorton5B Millard6B Okanogan5A Mineral6A Eau Claire
    3A Titus*6B Morgan4C Pacific4A Mingo7 Florence
    3B Tom Green5B Piute6B Pend Oreille5A Monongalia6A Fond du Lac
    2A Travis*6B Rich4C Pierce4A Monroe7Forest
    2A Trinity*5B Salt Lake4C San Juan4A Morgan6A Grant
    2A Tyler*5B San Juan4C Skagit5A Nicholas6A Green
    3A Upshur*5B Sanpete5B Skamania5A Ohio6A Green Lake
    3B Upton5B Sevier4C Snohomish5A Pendleton6A Iowa
    2B Uvalde*6B Summit5B Spokane4A Pleasants7 Iron
    2B Val Verde*5B Tooele6B Stevens5A Pocahontas6A Jackson
    3A Van Zandt*6B Uintah4C Thurston5A Preston6A Jefferson
    2A Victoria*5B Utah4C Wahkiakum4A Putnam6A Juneau
    2A Walker*6B Wasatch5B Walla Walla5A Raleigh6A Kenosha
    2A Waller*3B Washington4C Whatcom5A Randolph6A Kewaunee
    3B Ward5B Wayne5B Whitman4A Ritchie6A La Crosse
    2A Washington*5B Weber5B Yakima4A Roane6A Lafayette
    2B Webb*VERMONTWEST VIRGINIA5A Summers7 Langlade
    2A Wharton*5A Taylor7 Lincoln
    3B Wheeler6A (all)5A Barbour5A Tucker6A Manitowoc
    3A WichitaVIRGINIA4A Berkeley4A Tyler6A Marathon
    3B Wilbarger4A Boone5A Upshur6A Marinette
    2A Willacy*4A (all)4A Braxton4A Wayne6A Marquette
    2A Williamson*WASHINGTON5A Brooke5A Webster6A Menominee
    2A Wilson*4A Cabell5A Wetzel6A Milwaukee
    3B Winkler5B Adams4A Calhoun4A Wirt6A Monroe
    3A Wise5B Asotin4A Clay4A Wood6A Oconto
    3A Wood*5B Benton5A Doddridge4A Wyoming7 Oneida
    4B Yoakum5B Chelan5A Fayette6A Outagamie
    4C Clallam

    (continued)

    TABLE C301.1—continued
    CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID
    DESIGNATIONS BY STATE, COUNTY AND TERRITORY

    6A Ozaukee7 Taylor6B Big Horn6B SheridanNORTHERN
    MARIANA
    ISLANDS
    6A Pepin6A Trempealeau6B Campbell7 Sublette
    6A Pierce6A Vernon6B Carbon6B Sweetwater1A (all)*
    6A Polk7 Vilas6B Converse7 TetonPUERTO RICO
    6A Portage6A Walworth6B Crook6B Uinta
    7 Price7 Washburn6B Fremont6B Washakie1A (all)*
    6A Racine6A Washington5B Goshen6B WestonVIRGIN ISLANDS
    6A Richland6A Waukesha6B Hot SpringsUS TERRITORIES
    6A Rock6A Waupaca6B Johnson1A (all)*
    6A Rusk6A Waushara6B LaramieAMERICAN
    SAMOA
    6A Sauk6A Winnebago7 Lincoln
    7 Sawyer6A Wood6B Natrona1A (all)*
    6A ShawanoWYOMING6B NiobraraGUAM
    6A Sheboygan6B Park
    6A St. Croix6B Albany5B Platte1A (all)*

    C301.2 Warm humid counties.
    Warm humid counties are identified in Table C301.1 by an asterisk.

    C301.3 International climate zones.
    The climate zone for any location outside the United States shall be determined by applying Table C301.3(1) and then Table C301.3(2).

    TABLE C301.3(1)
    INTERNATIONAL CLIMATE ZONE DEFINITIONS

    MAJOR CLIMATE TYPE DEFINITIONS
    Marine (C) Definition—Locations meeting all four criteria:
    1.Mean temperature of coldest month between -3°C (27°F) and 18°C (65°F).
    2.Warmest month mean < 22°C (72°F).
    3.At least four months with mean temperatures over 10°C (50°F).
    4.Dry season in summer. The month with the heaviest precipitation in the cold season has at least three times as much precipitation as the month with the least precipitation in the rest of the year. The cold season is October through March in the Northern Hemisphere and April through September in the Southern Hemisphere.
    Dry (B) Definition—Locations meeting the following criteria:
    Not marine and Pin < 0.44 × (TF - 19.5) [Pcm < 2.0 × (TC + 7) in SI units]
    where:
    Pin = Annual precipitation in inches (cm)
    T = Annual mean temperature in °F (°C)
    Moist (A) Definition—Locations that are not marine and not dry.
    Warm-humid Definition—Moist (A) locations where either of the following wet-bulb temperature conditions shall occur during the warmest six consecutive months of the year:
    1. 67°F (19.4°C) or higher for 3,000 or more hours; or
    2. 73°F (22.8°C) or higher for 1,500 or more hours.
    For SI: °C = [(°F)-32]/1.8, 1 inch = 2.54 cm.

    TABLE C301.3(2)
    INTERNATIONAL CLIMATE ZONE DEFINITIONS

    ZONE
    NUMBER
    THERMAL CRITERIA
    IP Units SI Units
    1 9000 < CDD50°F 5000 < CDD10°C
    2 6300 < CDD50°F ≤ 9000 3500 < CDD10°C ≤ 5000
    3A and 3B 4500 < CDD50°F ≤ 6300 AND HDD65°F ≤ 5400 2500 < CDD10°C ≤ 3500 AND HDD18°C ≤ 3000
    4A and 4B CDD50°F ≤ 4500 AND HDD65°F ≤ 5400 CDD10°C ≤ 2500 AND HDD18°C ≤ 3000
    3C HDD65°F ≤ 3600 HDD18°C ≤ 2000
    4C 3600 < HDD65°F ≤ 5400 2000 < HDD18°C ≤ 3000
    5 5400 < HDD65°F ≤ 7200 3000 < HDD18°C ≤ 4000
    6 7200 < HDD65°F ≤ 9000 4000 < HDD18°C ≤ 5000
    7 9000 < HDD65°F ≤ 12600 5000 < HDD18°C ≤ 7000
    8 12600 < HDD65°F 7000 < HDD18°C
    For SI: °C = [(°F)-32]/1.8.

    SECTION C302
    DESIGN CONDITIONS

    C302.1 Interior design conditions.
    The interior design temperatures used for heating and cooling load calculations shall be a maximum of 72°F (22°C) for heating and minimum of 75°F (24°C) for cooling.

    SECTION C303
    MATERIALS, SYSTEMS AND EQUIPMENT

    C303.1 Identification.
    Materials, systems and equipment shall be identified in a manner that will allow a determination of compliance with the applicable provisions of this code.

    C303.1.1 Building thermal envelope insulation.
    An R-value identification mark shall be applied by the manufacturer to each piece of building thermal envelope insulation 12 inches (305 mm) or greater in width. Alternately, the insulation installers shall provide a certification listing the type, manufacturer and R-value of insulation installed in each element of the building thermal envelope. For blown or sprayed insulation (fiberglass and cellulose), the initial installed thickness, settled thickness, settled R-value, installed density, coverage area and number of bags installed shall be listed on the certification. For sprayed polyurethane foam (SPF) insulation, the installed thickness of the areas covered and R-value of installed thickness shall be listed on the certification. The insulation installer shall sign, date and post the certification in a conspicuous location on the job site.

    C303.1.1.1 Blown or sprayed roof/ceiling insulation.
    The thickness of blown-in or sprayed roof/ceiling insulation (fiberglass or cellulose) shall be written in inches (mm) on markers that are installed at least one for every 300 square feet (28 m2) throughout the attic space. The markers shall be affixed to the trusses or joists and marked with the minimum initial installed thickness with numbers a minimum of 1 inch (25 mm) in height. Each marker shall face the attic access opening. Spray polyurethane foam thickness and installed R-value shall be listed on certification provided by the insulation installer.

    C303.1.2 Insulation mark installation.
    Insulating materials shall be installed such that the manufacturer’s R-value mark is readily observable upon inspection.

    C303.1.3 Fenestration product rating.
    U-factors of fenestration products (windows, doors and skylights) shall be determined in accordance with NFRC 100 by an accredited, independent laboratory, and labeled and certified by the manufacturer. Products lacking such a labeled U-factor shall be assigned a default U-factor from Table C303.1.3(1) or C303.1.3(2). The solar heat gain coefficient (SHGC) and visible transmittance (VT) of glazed fenestration products (windows, glazed doors and skylights) shall be determined in accordance with NFRC 200 by an accredited, independent laboratory, and labeled and certified by the manufacturer. Products lacking such a labeled SHGC or VT shall be assigned a default SHGC or VT from Table C303.1.3(3).

    TABLE C303.1.3(1)
    DEFAULT GLAZED FENESTRATION U-FACTOR

    FRAME TYPESINGLE
    PANE
    DOUBLE
    PANE
    SKYLIGHT
    SingleDouble
    Metal1.200.802.001.30
    Metal with Thermal Break1.100.651.901.10
    Nonmetal or Metal Clad0.950.551.751.05
    Glazed Block0.60

    TABLE C303.1.3(2)
    DEFAULT DOOR U-FACTORS

    DOOR TYPEU-FACTOR
    Uninsulated Metal1.20
    Insulated Metal0.60
    Wood0.50
    Insulated, nonmetal edge, max 45% glazing, any glazing double pane0.35

    TABLE C303.1.3(3)
    DEFAULT GLAZED FENESTRATION SHGC AND VT

    SINGLE GLAZEDDOUBLE GLAZED GLAZED
    BLOCK
    ClearTintedClearTinted
    SHGC0.80.70.70.60.6
    VT0.60.30.60.30.6

    C303.1.4 Insulation product rating.
    The thermal resistance (R-value) of insulation shall be determined in accordance with the U.S. Federal Trade Commission R-value rule (CFR Title 16, Part 460) in units of h × ft2 × °F/Btu at a mean temperature of 75°F (24°C).

    C303.2 Installation.
    All materials, systems and equipment shall be installed in accordance with the manufacturer’s installation instructions and the International Building Code.

    C303.2.1 Protection of exposed foundation insulation.
    Insulation applied to the exterior of basement walls, crawlspace walls and the perimeter of slab-on-grade floors shall have a rigid, opaque and weather-resistant protective covering to prevent the degradation of the insulation’s thermal performance. The protective covering shall cover the exposed exterior insulation and extend a minimum of 6 inches (153 mm) below grade.

    C303.3 Maintenance information.
    Maintenance instructions shall be furnished for equipment and systems that require preventive maintenance. Required regular maintenance actions shall be clearly stated and incorporated on a readily accessible label. The label shall include the title or publication number for the operation and maintenance manual for that particular model and type of product.