Map of the eight IECC climate zones across the United States

What this diagram shows

A simplified map of the United States colored by IECC climate zone, from warm zone 1 in the south (red) through mixed zone 4 in the middle to cold zone 8 in the far north (navy). Florida and the Gulf coast fall in the hot zones 1 and 2; the deep South in warm zone 3; the middle of the country in mixed zone 4 and cool zone 5; and the northern tier, including Minnesota and Maine, in the cold zones 6, 7, and 8. A legend names each zone’s climate. The colder the zone (the higher the number), the more insulation the energy code requires, so finding your zone is the first step.