South Dakota Climate Zones by County
South Dakota's 66 counties span climate zones 5A to 6A under the 2021 International Energy Conservation Code (IECC). Zone 6A is the most common, with 48 of the 66. For reference, Sioux Falls, Rapid City and Pierre are in zone 6A.
Insulation minimums for each zone in South Dakota
| Zone | Counties | Attic | Wood-frame walls | Floors over unheated space | Basement walls |
|---|---|---|---|---|---|
| 5A | 18 | R-60 | R-30, or 20+5ci, or 13+10ci, or R-20ci | R-30 | R-15ci, or R-19, or 13+5ci |
| 6A | 48 | R-60 | R-30, or 20+5ci, or 13+10ci, or R-20ci | R-30 | R-15ci, or R-19, or 13+5ci |
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 South Dakota uses
South Dakota has no statewide residential energy code; cities and counties adopt their own, so check with your local building department. 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
Five counties moved one zone warmer in the 2021 map: Brule County (6 → 5), Haakon County (6 → 5), Jones County (6 → 5), Lyman County (6 → 5), Stanley County (6 → 5). If your town still enforces the 2018 or 2015 code, the older zone applies to permits.
Every county in South Dakota
| Name | Zone (2021) | Zone (2018) | Details |
|---|---|---|---|
| Aurora County | 6A | 6A | Insulation → |
| Beadle County | 6A | 6A | Insulation → |
| Bennett County | 5A | 5A | Insulation → |
| Bon Homme County | 5A | 5A | Insulation → |
| Brookings County | 6A | 6A | Insulation → |
| Brown County | 6A | 6A | Insulation → |
| Brule County | 5A | 6A changed | Insulation → |
| Buffalo County | 6A | 6A | Insulation → |
| Butte County | 6A | 6A | Insulation → |
| Campbell County | 6A | 6A | Insulation → |
| Charles Mix County | 5A | 5A | Insulation → |
| Clark County | 6A | 6A | Insulation → |
| Clay County | 5A | 5A | Insulation → |
| Codington County | 6A | 6A | Insulation → |
| Corson County | 6A | 6A | Insulation → |
| Custer County | 6A | 6A | Insulation → |
| Davison County | 6A | 6A | Insulation → |
| Day County | 6A | 6A | Insulation → |
| Deuel County | 6A | 6A | Insulation → |
| Dewey County | 6A | 6A | Insulation → |
| Douglas County | 5A | 5A | Insulation → |
| Edmunds County | 6A | 6A | Insulation → |
| Fall River County | 6A | 6A | Insulation → |
| Faulk County | 6A | 6A | Insulation → |
| Grant County | 6A | 6A | Insulation → |
| Gregory County | 5A | 5A | Insulation → |
| Haakon County | 5A | 6A changed | Insulation → |
| Hamlin County | 6A | 6A | Insulation → |
| Hand County | 6A | 6A | Insulation → |
| Hanson County | 6A | 6A | Insulation → |
| Harding County | 6A | 6A | Insulation → |
| Hughes County | 6A | 6A | Insulation → |
| Hutchinson County | 5A | 5A | Insulation → |
| Hyde County | 6A | 6A | Insulation → |
| Jackson County | 5A | 5A | Insulation → |
| Jerauld County | 6A | 6A | Insulation → |
| Jones County | 5A | 6A changed | Insulation → |
| Kingsbury County | 6A | 6A | Insulation → |
| Lake County | 6A | 6A | Insulation → |
| Lawrence County | 6A | 6A | Insulation → |
| Lincoln County | 6A | 6A | Insulation → |
| Lyman County | 5A | 6A changed | Insulation → |
| Marshall County | 6A | 6A | Insulation → |
| McCook County | 6A | 6A | Insulation → |
| McPherson County | 6A | 6A | Insulation → |
| Meade County | 6A | 6A | Insulation → |
| Mellette County | 5A | 5A | Insulation → |
| Miner County | 6A | 6A | Insulation → |
| Minnehaha County | 6A | 6A | Insulation → |
| Moody County | 6A | 6A | Insulation → |
| Pennington County | 6A | 6A | Insulation → |
| Perkins County | 6A | 6A | Insulation → |
| Potter County | 6A | 6A | Insulation → |
| Roberts County | 6A | 6A | Insulation → |
| Sanborn County | 6A | 6A | Insulation → |
| Shannon County | 6A | 6A | Insulation → |
| Spink County | 6A | 6A | Insulation → |
| Stanley County | 5A | 6A changed | Insulation → |
| Sully County | 6A | 6A | Insulation → |
| Todd County | 5A | 5A | Insulation → |
| Tripp County | 5A | 5A | Insulation → |
| Turner County | 6A | 6A | Insulation → |
| Union County | 5A | 5A | Insulation → |
| Walworth County | 6A | 6A | Insulation → |
| Yankton County | 5A | 5A | Insulation → |
| Ziebach County | 6A | 6A | Insulation → |
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 South Dakota?
South Dakota spans IECC climate zones 5A to 6A; zone 6A is the most common. Find your county in the table above, or search by ZIP code.
How much attic insulation do I need in South Dakota?
The 2021 IECC calls for R-60 in the attic everywhere in South Dakota.
What energy code does South Dakota use?
South Dakota has no statewide residential energy code; cities and counties adopt their own, so check with your local building department. Source: US Department of Energy, September 2026. Local governments can adopt newer codes or amendments.
More for South Dakota: Last frost dates in South Dakota · South Dakota planting zones · Frost line depth by state