Map of the IECC climate zones across the United States, with climate zone 4 highlighted

What this diagram shows

A simplified map of the United States colored by IECC climate zone, from warm zone 1 in the south (red) 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 and 7. A legend names each zone’s climate. Climate zone 4 (mixed) is highlighted, because a colder zone requires a higher insulation R-value. The figure also lists example cities in the highlighted zone and the IECC minimum insulation R-values for the attic, walls, and floor.