More risky heat days in 232 US locations

Climate Central analyzed 247 U.S. locations from 1970 to 2022, finding that 232 locations experienced an increase in annual 'risky heat days'—days where temperatures exceed the local minimum mortality temperature (MMT). On average, these locations saw an increase of 21 such days per year. While increases occurred in every U.S. region, the South and Southeast were hotspots, with 91% of the 22 locations seeing the highest increases (40+ days) located there. The analysis emphasizes that extreme heat is the deadliest natural hazard in the U.S. and disproportionately affects vulnerable populations, including children, seniors, and low-income communities of color.

• Between 1970 and 2022, 95% of the 244 analyzed U.S. locations (232 locations) saw an increase in the annual number of risky heat days, which are days exceeding the local minimum mortality temperature (MMT). These 232 locations experienced an average increase of 21 risky heat days per year.
• The South and Southeast regions of the U.S. were identified as risky heat hotspots. Of the 22 locations that saw an increase of 40 or more risky heat days, 91% were in the South or Southeast, and over two-thirds were located in Texas (nine) or Florida (six).
• The highest increases in annual days above MMT were recorded in Reno, Nevada (64 days), Panama City, Florida (60 days), and the Tampa Area, Florida (58 days). Despite the concentration in the South, increases in risky heat days were observed across every U.S. region.
• Extreme heat is the deadliest natural hazard in the U.S., with one study estimating 12,000 premature deaths in the contiguous U.S. between 2000 and 2010. Vulnerable groups include children, adults over 65, pregnant people, and those with illnesses, as well as outdoor workers and athletes.
• Structural inequities exacerbate heat exposure. In 169 large U.S. urban areas, people of color and those below the poverty line are disproportionately exposed to urban heat island intensity. A 2021 EPA analysis found that in 49 U.S. cities, Black individuals and low-income individuals are 40% and 11% more likely, respectively, to live in areas projected to have the highest future increases in heat-related mortality.

APA

Climate Central (2023). More risky heat days in 232 US locations. https://www.climatecentral.org/climate-matters/more-risky-heat-days-in-232-us-locations

Chicago

Climate Central. More risky heat days in 232 US locations. 2023. https://www.climatecentral.org/climate-matters/more-risky-heat-days-in-232-us-locations.

Wikipedia

{{cite report |author=Climate Central |title=More risky heat days in 232 US locations |date=10 May 2023 |url=https://www.climatecentral.org/climate-matters/more-risky-heat-days-in-232-us-locations |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{climatecentral2023more, author = {{Climate Central}}, title = {{More risky heat days in 232 US locations}}, institution = {Climate Central}, year = {2023}, month = may, url = {https://www.climatecentral.org/climate-matters/more-risky-heat-days-in-232-us-locations}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }