US Counties With the Lowest Days of 90°F or Hotter

3,108 US counties ranked by days of 90°F or hotter, from lowest to highest. First are Bear Lake County, ID (0), Camas County, ID (0) and Custer County, ID (0). The middle one of the 3,108 has 22.

What this measures

The number of days in the year when the high temperature reached 90°F or more. The high is the average over the county of NOAA's daily map of weather station readings, made of squares about 3 miles wide. So a county with hot valleys and cool mountains counts fewer days than its hottest town. A state's figure is the average of its counties, each weighted by its land area. Lower 48 states only, from 1951. Source: NOAA NCEI nClimGrid-Daily.

For most measures, a national ranking mostly sorts places by income and by how urban they are. Each county’s own page compares it with the 50 counties most like it instead, which is often the fairer view.

The 100 lowest counties

Every state, lowest first

Each state’s own published figure, not an average of its counties.

More on days of 90°F or hotter

• US Counties With the Highest Days of 90°F or Hotter
• Days of 90°F or hotter by US county: map by year and what it goes with

A ranking describes places, not the people in them, and a high or low place does not by itself say why. All US rankings.