Extreme Heat: When Outdoor Sports Become Risky

A Climate Central analysis of 239 U.S. cities reveals that 83% have seen an increase in annual average days with a heat index of 90°F or higher since 1979. The report highlights the danger of exertional heat illness (EHI), noting that heat-related illnesses are a leading cause of death or disability among high school athletes. It details regional trends, such as substantial increases in the Pacific Northwest and extended heat seasons in the South, while noting that climate change is intensifying these trends. The document provides safety recommendations for coaches and athletes, including the use of wet bulb globe temperature (WBGT) monitoring and gradual heat acclimatization.

• An analysis of 239 locations in the contiguous United States found that 198 cities (83%) experienced an increase in the annual average number of days with a heat index of 90°F or higher over the last four decades.
• The frequency of 'danger' days—where the heat index reaches 105°F or higher—has trended upward since 1979 in 106 of the 239 analyzed U.S. cities, with McAllen, Texas, seeing the largest increase of 21.9 danger days.
• Regional trends show substantial increases in extreme heat index days in the Pacific Northwest, including Yakima, Washington, where the average annual number of such days more than doubled from 13 to 29.4.
• In the Southern U.S., extreme heat now extends beyond summer months, with Laredo, Texas, averaging 170.4 days above 90°F, one in five of which are 'danger' days (above 105°F).
• Heat-related illnesses are a primary cause of death or disability for high school athletes; since 1995, 64 football players died from heat stroke, with 90% of these deaths occurring during practice.
• Extreme heat is impacting global sporting events, leading to the rescheduling of the 2020 Tokyo Olympic marathon to 6 a.m. and the implementation of a heat rule for male players at the U.S. Open.
• The Korey Stringer Institute recommends that schools use wet bulb globe temperature (WBGT) monitoring to accurately measure local heat, humidity, wind, and solar radiation, as traditional heat index values can increase by up to 15°F in direct sunlight.

APA

Climate Central (2019). Extreme Heat: When Outdoor Sports Become Risky. https://www.climatecentral.org/report/extreme-heat-when-outdoor-sports-become-risky-2019

Chicago

Climate Central. Extreme Heat: When Outdoor Sports Become Risky. 2019. https://www.climatecentral.org/report/extreme-heat-when-outdoor-sports-become-risky-2019.

Wikipedia

{{cite report |author=Climate Central |title=Extreme Heat: When Outdoor Sports Become Risky |date=21 August 2019 |url=https://www.climatecentral.org/report/extreme-heat-when-outdoor-sports-become-risky-2019 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{climatecentral2019extreme, author = {{Climate Central}}, title = {{Extreme Heat: When Outdoor Sports Become Risky}}, institution = {Climate Central}, year = {2019}, month = aug, url = {https://www.climatecentral.org/report/extreme-heat-when-outdoor-sports-become-risky-2019}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }