Excessive Heat in the United States

How dangerous are Excessive Heat events in the U.S.?

NOAA's Storm Events Database has catalogued 18,147 excessive heat events across 52 states and territories between 2015 and 2025. The cumulative human toll is 2,498 fatalities and 3,381 injuries, and the financial footprint reaches $7.6M in combined property ($7.6M) and crop ($74.0K) damage. On a per-fatality basis this places excessive heat events at a very high severity tier relative to other tracked hazard types in the NOAA catalog.

Geographic exposure is heavily concentrated in a handful of high-severity states. The three states absorbing the largest share of events are AZ (2,029 events, 1,687 fatalities), OK (1,973 events, 2 fatalities), TX (1,905 events, 49 fatalities), reflecting both physical geography (coastal exposure, plains corridors, terrain) and dense population sitting directly in harm's way. At the other end, states such as WY, RI, AS report far fewer events, a genuinely rare event outside the leading states, not merely an underreported one.

The year-to-year record shows real volatility around a high baseline. The peak year on record was 2023, logging 5,024 events and $0 in property damage in a single calendar year. The most recent year in the dataset is 2025 with 2,878 events recorded. Across the full 11-year window, annual event counts reflect seasonal climate cycles (ENSO phases, active vs. quiet severe-weather years) and long-term shifts tied to a warming climate both help explain the swings.