Climate zones by state

Arkansas Climate Zones by County

Arkansas's 75 counties span climate zones 3A to 4A under the 2021 International Energy Conservation Code (IECC). Zone 3A is the most common, with 63 of the 75. For reference, Little Rock and Fort Smith are in zone 3A and Fayetteville is in 4A.

Insulation minimums for each zone in Arkansas

ZoneCountiesAtticWood-frame wallsFloors over unheated spaceBasement walls
3A63R-49R-20, or 13+5ci, or R-15ciR-19R-5ci or R-13
4A12R-60R-30, or 20+5ci, or 13+10ci, or R-20ciR-19R-10ci or R-13

Minimums from the 2021 IECC (Table R402.1.3). Many areas still enforce an older edition, so check with your local building department. See sources.

Which energy code Arkansas uses

Arkansas enforces the 2009 IECC with amendments for homes (in effect since Jan 2015). Source: US Department of Energy, September 2026. Local governments can adopt newer codes or amendments. See every state's energy code.

What changed from the 2018 map

None of Arkansas's counties changed zone between the 2018 and 2021 maps.

Every county in Arkansas

NameZone (2021)Zone (2018)Details
Arkansas County3A3AInsulation →
Ashley County3A3AInsulation →
Baxter County4A4AInsulation →
Benton County4A4AInsulation →
Boone County4A4AInsulation →
Bradley County3A3AInsulation →
Calhoun County3A3AInsulation →
Carroll County4A4AInsulation →
Chicot County3A3AInsulation →
Clark County3A3AInsulation →
Clay County3A3AInsulation →
Cleburne County3A3AInsulation →
Cleveland County3A3AInsulation →
Columbia County3A3AInsulation →
Conway County3A3AInsulation →
Craighead County3A3AInsulation →
Crawford County3A3AInsulation →
Crittenden County3A3AInsulation →
Cross County3A3AInsulation →
Dallas County3A3AInsulation →
Desha County3A3AInsulation →
Drew County3A3AInsulation →
Faulkner County3A3AInsulation →
Franklin County3A3AInsulation →
Fulton County4A4AInsulation →
Garland County3A3AInsulation →
Grant County3A3AInsulation →
Greene County3A3AInsulation →
Hempstead County3A3AInsulation →
Hot Spring County3A3AInsulation →
Howard County3A3AInsulation →
Independence County3A3AInsulation →
Izard County4A4AInsulation →
Jackson County3A3AInsulation →
Jefferson County3A3AInsulation →
Johnson County3A3AInsulation →
Lafayette County3A3AInsulation →
Lawrence County3A3AInsulation →
Lee County3A3AInsulation →
Lincoln County3A3AInsulation →
Little River County3A3AInsulation →
Logan County3A3AInsulation →
Lonoke County3A3AInsulation →
Madison County4A4AInsulation →
Marion County4A4AInsulation →
Miller County3A3AInsulation →
Mississippi County3A3AInsulation →
Monroe County3A3AInsulation →
Montgomery County3A3AInsulation →
Nevada County3A3AInsulation →
Newton County4A4AInsulation →
Ouachita County3A3AInsulation →
Perry County3A3AInsulation →
Phillips County3A3AInsulation →
Pike County3A3AInsulation →
Poinsett County3A3AInsulation →
Polk County3A3AInsulation →
Pope County3A3AInsulation →
Prairie County3A3AInsulation →
Pulaski County3A3AInsulation →
Randolph County3A3AInsulation →
Saline County3A3AInsulation →
Scott County3A3AInsulation →
Searcy County4A4AInsulation →
Sebastian County3A3AInsulation →
Sevier County3A3AInsulation →
Sharp County3A3AInsulation →
St. Francis County3A3AInsulation →
Stone County4A4AInsulation →
Union County3A3AInsulation →
Van Buren County3A3AInsulation →
Washington County4A4AInsulation →
White County3A3AInsulation →
Woodruff County3A3AInsulation →
Yell County3A3AInsulation →

Source: Pacific Northwest National Laboratory, Guide to Determining Climate Zone by County: Building America and IECC 2021 Updates (2022).

Frequently asked questions

What climate zone is Arkansas?

Arkansas spans IECC climate zones 3A to 4A; zone 3A is the most common. Find your county in the table above, or search by ZIP code.

How much attic insulation do I need in Arkansas?

In Arkansas, the 2021 IECC calls for R-49 and R-60 in the attic, depending on the zone. The table near the top of this page lists each zone's minimums.

What energy code does Arkansas use?

Arkansas enforces the 2009 IECC with amendments for homes (in effect since Jan 2015). Source: US Department of Energy, September 2026. Local governments can adopt newer codes or amendments.

More for Arkansas: Last frost dates in Arkansas · Arkansas planting zones · Frost line depth by state