Texas climate zones
Texas’s 254 counties fall in 6 IECC 2021 climate zones: 1A (3), 2A (81), 2B (14), 3A (58), 3B (70), 4B (28).
Zone 1A: very hot-humid
Attic target R30 (ENERGY STAR)Cameron County (Hot-humid) · Hidalgo County (Hot-humid) · Willacy County (Hot-humid)
Zone 2A: hot-humid
Attic target R49 (ENERGY STAR)Anderson County (Hot-humid) · Angelina County (Hot-humid) · Aransas County (Hot-humid) · Atascosa County (Hot-humid) · Austin County (Hot-humid) · Bastrop County (Hot-humid) · Bee County (Hot-humid) · Bell County (Hot-humid) · Bexar County (Hot-humid) · Bosque County (Hot-humid) · Brazoria County (Hot-humid) · Brazos County (Hot-humid) · Brooks County (Hot-humid) · Burleson County (Hot-humid) · Caldwell County (Hot-humid) · Calhoun County (Hot-humid) · Chambers County (Hot-humid) · Cherokee County (Hot-humid) · Colorado County (Hot-humid) · Comal County (Hot-humid) · Coryell County (Hot-humid) · Dallas County (Hot-humid) · DeWitt County (Hot-humid) · Duval County (Hot-humid) · Ellis County (Hot-humid) · Falls County (Hot-humid) · Fayette County (Hot-humid) · Fort Bend County (Hot-humid) · Freestone County (Hot-humid) · Galveston County (Hot-humid) · Goliad County (Hot-humid) · Gonzales County (Hot-humid) · Grimes County (Hot-humid) · Guadalupe County (Hot-humid) · Hardin County (Hot-humid) · Harris County (Hot-humid) · Hays County (Hot-humid) · Hill County (Hot-humid) · Houston County (Hot-humid) · Jackson County (Hot-humid) · Jasper County (Hot-humid) · Jefferson County (Hot-humid) · Jim Hogg County (Hot-humid) · Jim Wells County (Hot-humid) · Johnson County (Hot-humid) · Karnes County (Hot-humid) · Kenedy County (Hot-humid) · Kleberg County (Hot-humid) · Lavaca County (Hot-humid) · Lee County (Hot-humid) · Leon County (Hot-humid) · Liberty County (Hot-humid) · Limestone County (Hot-humid) · Live Oak County (Hot-humid) · Madison County (Hot-humid) · Matagorda County (Hot-humid) · McLennan County (Hot-humid) · McMullen County (Hot-humid) · Milam County (Hot-humid) · Montgomery County (Hot-humid) · Navarro County (Hot-humid) · Newton County (Hot-humid) · Nueces County (Hot-humid) · Orange County (Hot-humid) · Polk County (Hot-humid) · Refugio County (Hot-humid) · Robertson County (Hot-humid) · San Jacinto County (Hot-humid) · San Patricio County (Hot-humid) · Starr County (Hot-humid) · Tarrant County (Hot-humid) · Travis County (Hot-humid) · Trinity County (Hot-humid) · Tyler County (Hot-humid) · Victoria County (Hot-humid) · Walker County (Hot-humid) · Waller County (Hot-humid) · Washington County (Hot-humid) · Wharton County (Hot-humid) · Williamson County (Hot-humid) · Wilson County (Hot-humid)
Zone 2B: hot-dry
Attic target R49 (ENERGY STAR)Bandera County (Hot-humid) · Dimmit County (Hot-humid) · Edwards County (Hot-humid) · Frio County (Hot-humid) · Kinney County (Hot-humid) · La Salle County (Hot-humid) · Maverick County (Hot-humid) · Medina County (Hot-humid) · Real County (Hot-humid) · Uvalde County (Hot-humid) · Val Verde County (Hot-humid) · Webb County (Hot-humid) · Zapata County (Hot-humid) · Zavala County (Hot-humid)
Zone 3A: warm-humid
Attic target R49 (ENERGY STAR)Archer County (Mixed-humid) · Blanco County (Hot-humid) · Bowie County (Hot-humid) · Brown County (Hot-humid) · Burnet County (Hot-humid) · Camp County (Hot-humid) · Cass County (Hot-humid) · Clay County (Mixed-humid) · Collin County (Hot-humid) · Comanche County (Hot-humid) · Cooke County (Mixed-humid) · Delta County (Hot-humid) · Denton County (Hot-humid) · Eastland County (Mixed-humid) · Erath County (Hot-humid) · Fannin County (Mixed-humid) · Franklin County (Hot-humid) · Gillespie County (Hot-humid) · Grayson County (Mixed-humid) · Gregg County (Hot-humid) · Hamilton County (Hot-humid) · Harrison County (Hot-humid) · Henderson County (Hot-humid) · Hood County (Hot-humid) · Hopkins County (Hot-humid) · Hunt County (Hot-humid) · Jack County (Mixed-humid) · Kaufman County (Hot-humid) · Kendall County (Hot-humid) · Lamar County (Hot-humid) · Lampasas County (Hot-humid) · Llano County (Hot-humid) · Marion County (Hot-humid) · Mills County (Hot-humid) · Montague County (Mixed-humid) · Morris County (Hot-humid) · Nacogdoches County (Hot-humid) · Palo Pinto County (Mixed-humid) · Panola County (Hot-humid) · Parker County (Hot-humid) · Rains County (Hot-humid) · Red River County (Hot-humid) · Rockwall County (Hot-humid) · Rusk County (Hot-humid) · Sabine County (Hot-humid) · San Augustine County (Hot-humid) · San Saba County (Hot-humid) · Shelby County (Hot-humid) · Smith County (Hot-humid) · Somervell County (Hot-humid) · Stephens County (Mixed-humid) · Titus County (Hot-humid) · Upshur County (Hot-humid) · Van Zandt County (Hot-humid) · Wichita County (Mixed-humid) · Wise County (Mixed-humid) · Wood County (Hot-humid) · Young County (Mixed-humid)
Zone 3B: warm-dry
Attic target R49 (ENERGY STAR)Andrews County (Hot-dry) · Baylor County (Hot-dry) · Borden County (Hot-dry) · Brewster County (Hot-dry) · Callahan County (Hot-dry) · Childress County (Hot-dry) · Coke County (Hot-dry) · Coleman County (Hot-dry) · Collingsworth County (Hot-dry) · Concho County (Hot-dry) · Cottle County (Hot-dry) · Crane County (Hot-dry) · Crockett County (Hot-dry) · Crosby County (Hot-dry) · Culberson County (Hot-dry) · Dawson County (Hot-dry) · Dickens County (Hot-dry) · Ector County (Hot-dry) · El Paso County (Hot-dry) · Fisher County (Hot-dry) · Foard County (Hot-dry) · Gaines County (Hot-dry) · Garza County (Hot-dry) · Glasscock County (Hot-dry) · Hall County (Hot-dry) · Hardeman County (Hot-dry) · Haskell County (Hot-dry) · Hemphill County (Hot-dry) · Howard County (Hot-dry) · Hudspeth County (Hot-dry) · Irion County (Hot-dry) · Jeff Davis County (Hot-dry) · Jones County (Hot-dry) · Kent County (Hot-dry) · Kerr County (Hot-dry) · Kimble County (Hot-dry) · King County (Hot-dry) · Knox County (Hot-dry) · Loving County (Hot-dry) · Lubbock County (Hot-dry) · Lynn County (Hot-dry) · Martin County (Hot-dry) · Mason County (Hot-dry) · McCulloch County (Hot-dry) · Menard County (Hot-dry) · Midland County (Hot-dry) · Mitchell County (Hot-dry) · Motley County (Hot-dry) · Nolan County (Hot-dry) · Pecos County (Hot-dry) · Presidio County (Hot-dry) · Reagan County (Hot-dry) · Reeves County (Hot-dry) · Runnels County (Hot-dry) · Schleicher County (Hot-dry) · Scurry County (Hot-dry) · Shackelford County (Hot-dry) · Sterling County (Hot-dry) · Stonewall County (Hot-dry) · Sutton County (Hot-dry) · Taylor County (Hot-dry) · Terrell County (Hot-dry) · Terry County (Hot-dry) · Throckmorton County (Hot-dry) · Tom Green County (Hot-dry) · Upton County (Hot-dry) · Ward County (Hot-dry) · Wheeler County (Hot-dry) · Wilbarger County (Hot-dry) · Winkler County (Hot-dry)
Zone 4B: mixed-dry
Attic target R60 (ENERGY STAR)Armstrong County (Mixed-dry) · Bailey County (Mixed-dry) · Briscoe County (Mixed-dry) · Carson County (Mixed-dry) · Castro County (Mixed-dry) · Cochran County (Mixed-dry) · Dallam County (Mixed-dry) · Deaf Smith County (Mixed-dry) · Donley County (Mixed-dry) · Floyd County (Mixed-dry) · Gray County (Mixed-dry) · Hale County (Mixed-dry) · Hansford County (Mixed-dry) · Hartley County (Mixed-dry) · Hockley County (Mixed-dry) · Hutchinson County (Mixed-dry) · Lamb County (Mixed-dry) · Lipscomb County (Mixed-dry) · Moore County (Mixed-dry) · Ochiltree County (Mixed-dry) · Oldham County (Mixed-dry) · Parmer County (Mixed-dry) · Potter County (Mixed-dry) · Randall County (Mixed-dry) · Roberts County (Mixed-dry) · Sherman County (Mixed-dry) · Swisher County (Mixed-dry) · Yoakum County (Mixed-dry)