US Counties With the Highest Clear Days

3,144 US counties ranked by clear days, from highest to lowest. First are Yuma County, AZ (273), La Paz County, AZ (272) and Imperial County, CA (258). The middle one of the 3,144 has 118.

What this measures

The number of days in the year when clouds blocked less than 7% of the sunlight, so the ground got at least 93% of what a cloudless sky would give. It is the closest measure here to a count of sunny days. It is a NASA estimate from weather satellites for squares of land about 60 miles across, not a count by someone watching the sky, and nearby counties often share a value. The 93% line was chosen so that, on average, the count matches NOAA's counts of clear days at 64 weather stations. There, a clear day is one with three tenths of the sky or less covered by cloud in daylight. It starts in 2001, since the older satellites count clear days differently. Source: NASA POWER (Prediction Of Worldwide Energy Resources).

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 highest counties

Every state, highest first

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

More on clear days

• US Counties With the Lowest Clear Days
• Clear days 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.