Climate zones by state

Minnesota Climate Zones by County

Minnesota's 87 counties span climate zones 5A to 7 under the 2021 International Energy Conservation Code (IECC). Zone 6A is the most common, with 61 of the 87. For reference, Minneapolis and Rochester are in zone 6A and Duluth is in 7.

Insulation minimums for each zone in Minnesota

ZoneCountiesAtticWood-frame wallsFloors over unheated spaceBasement walls
5A3R-60R-30, or 20+5ci, or 13+10ci, or R-20ciR-30R-15ci, or R-19, or 13+5ci
6A61R-60R-30, or 20+5ci, or 13+10ci, or R-20ciR-30R-15ci, or R-19, or 13+5ci
723R-60R-30, or 20+5ci, or 13+10ci, or R-20ciR-38R-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 Minnesota uses

Minnesota enforces the 2012 IECC with amendments for homes (in effect since Feb 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

Ten counties moved one zone warmer in the 2021 map: Becker County (7 → 6), Clay County (7 → 6), Fillmore County (6 → 5), Grant County (7 → 6), Houston County (6 → 5), Kanabec County (7 → 6), Mille Lacs County (7 → 6), Otter Tail County (7 → 6), Wilkin County (7 → 6), Winona County (6 → 5). If your town still enforces the 2018 or 2015 code, the older zone applies to permits.

Every county in Minnesota

NameZone (2021)Zone (2018)Details
Aitkin County77Insulation →
Anoka County6A6AInsulation →
Becker County6A7 changedInsulation →
Beltrami County77Insulation →
Benton County6A6AInsulation →
Big Stone County6A6AInsulation →
Blue Earth County6A6AInsulation →
Brown County6A6AInsulation →
Carlton County77Insulation →
Carver County6A6AInsulation →
Cass County77Insulation →
Chippewa County6A6AInsulation →
Chisago County6A6AInsulation →
Clay County6A7 changedInsulation →
Clearwater County77Insulation →
Cook County77Insulation →
Cottonwood County6A6AInsulation →
Crow Wing County77Insulation →
Dakota County6A6AInsulation →
Dodge County6A6AInsulation →
Douglas County6A6AInsulation →
Faribault County6A6AInsulation →
Fillmore County5A6A changedInsulation →
Freeborn County6A6AInsulation →
Goodhue County6A6AInsulation →
Grant County6A7 changedInsulation →
Hennepin County6A6AInsulation →
Houston County5A6A changedInsulation →
Hubbard County77Insulation →
Isanti County6A6AInsulation →
Itasca County77Insulation →
Jackson County6A6AInsulation →
Kanabec County6A7 changedInsulation →
Kandiyohi County6A6AInsulation →
Kittson County77Insulation →
Koochiching County77Insulation →
Lac qui Parle County6A6AInsulation →
Lake County77Insulation →
Lake of the Woods County77Insulation →
Le Sueur County6A6AInsulation →
Lincoln County6A6AInsulation →
Lyon County6A6AInsulation →
Mahnomen County77Insulation →
Marshall County77Insulation →
Martin County6A6AInsulation →
McLeod County6A6AInsulation →
Meeker County6A6AInsulation →
Mille Lacs County6A7 changedInsulation →
Morrison County6A6AInsulation →
Mower County6A6AInsulation →
Murray County6A6AInsulation →
Nicollet County6A6AInsulation →
Nobles County6A6AInsulation →
Norman County77Insulation →
Olmsted County6A6AInsulation →
Otter Tail County6A7 changedInsulation →
Pennington County77Insulation →
Pine County77Insulation →
Pipestone County6A6AInsulation →
Polk County77Insulation →
Pope County6A6AInsulation →
Ramsey County6A6AInsulation →
Red Lake County77Insulation →
Redwood County6A6AInsulation →
Renville County6A6AInsulation →
Rice County6A6AInsulation →
Rock County6A6AInsulation →
Roseau County77Insulation →
Scott County6A6AInsulation →
Sherburne County6A6AInsulation →
Sibley County6A6AInsulation →
St. Louis County77Insulation →
Stearns County6A6AInsulation →
Steele County6A6AInsulation →
Stevens County6A6AInsulation →
Swift County6A6AInsulation →
Todd County6A6AInsulation →
Traverse County6A6AInsulation →
Wabasha County6A6AInsulation →
Wadena County77Insulation →
Waseca County6A6AInsulation →
Washington County6A6AInsulation →
Watonwan County6A6AInsulation →
Wilkin County6A7 changedInsulation →
Winona County5A6A changedInsulation →
Wright County6A6AInsulation →
Yellow Medicine County6A6AInsulation →

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 Minnesota?

Minnesota spans IECC climate zones 5A to 7; 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 Minnesota?

The 2021 IECC calls for R-60 in the attic everywhere in Minnesota.

What energy code does Minnesota use?

Minnesota enforces the 2012 IECC with amendments for homes (in effect since Feb 2015). Source: US Department of Energy, September 2026. Local governments can adopt newer codes or amendments.

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