Most extreme-heat days, US counties
US counties ranked by the number of days in 2022 that reached at least 90°F, from the heat-exposure data (NOAA North American Regional Reanalysis) published with the Census Bureau's experimental Community Resilience Estimates for Heat. Yuma County, Arizona leads at 156. 3,144 counties qualify in total. Texas carries 22 of the top 25 entries.
UPDATED 2026-07-15 · DATA: US CENSUS BUREAU ACS 5-YEAR ESTIMATES
Frequently asked
Which county has the highest extreme-heat days (90°f+)?
Yuma County, Arizona ranks #1 with 156 (2022 American Community Survey).
What are the top 5 counties by extreme-heat days (90°f+)?
Yuma County, Arizona, Imperial County, California, Maricopa County, Arizona, Hidalgo County, Texas, Starr County, Texas.
How many counties are in this ranking?
3,144 counties qualify after filtering for population minimums and data availability. The ranking covers 2022 ACS 5-year data.
How is extreme-heat days (90°f+) measured?
Number of days in 2022 when the maximum temperature reached at least 90°F, from the heat-exposure data (NOAA North American Regional Reanalysis) distributed with the Census Bureau's experimental Community Resilience Estimates for Heat. Source: US Census Bureau, American Community Survey 5-year estimates (2022).