Idaho climate zones
Idaho’s 44 counties fall in 2 IECC 2021 climate zones: 5B (22), 6B (22).
Zone 5B: cool-dry
Attic target R60 (ENERGY STAR)Ada County (Cold) · Benewah County (Cold) · Canyon County (Cold) · Cassia County (Cold) · Clearwater County (Cold) · Elmore County (Cold) · Gem County (Cold) · Gooding County (Cold) · Idaho County (Cold) · Jerome County (Cold) · Kootenai County (Cold) · Latah County (Cold) · Lewis County (Cold) · Lincoln County (Cold) · Minidoka County (Cold) · Nez Perce County (Cold) · Owyhee County (Cold) · Payette County (Cold) · Power County (Cold) · Shoshone County (Cold) · Twin Falls County (Cold) · Washington County (Cold)
Zone 6B: cold-dry
Attic target R60 (ENERGY STAR)Adams County (Cold) · Bannock County (Cold) · Bear Lake County (Cold) · Bingham County (Cold) · Blaine County (Cold) · Boise County (Cold) · Bonner County (Cold) · Bonneville County (Cold) · Boundary County (Cold) · Butte County (Cold) · Camas County (Cold) · Caribou County (Cold) · Clark County (Cold) · Custer County (Cold) · Franklin County (Cold) · Fremont County (Cold) · Jefferson County (Cold) · Lemhi County (Cold) · Madison County (Cold) · Oneida County (Cold) · Teton County (Cold) · Valley County (Cold)