Danger for Seniors & Others as Southern Utah Hits 90 Degrees

A new University of Utah study adds a troubling layer to southern Utah’s heat story. Researchers reviewed more than 7,500 Utah suicide cases from 2000 to 2016 and found that unusually hot days were linked to higher suicide risk year-round. The study also found that during the warm season, high nitrogen dioxide levels can sharply worsen that risk: for every 9-degree increase in wet bulb globe temperature, suicide risk rose 5%, and when nitrogen dioxide was high, the increase was nearly 50%. The authors say the findings show heat and air pollution can interact in ways that make already-dangerous days worse.

90’s UNUSUALLY EARLY

That matters in Southern Utah, where prolonged heat is no longer unusual. In 2024, St. George logged at least 46 straight days of 100-degree heat by early August, part of what was reported as the city’s second-longest triple-digit streak on record at that point. This March, St. George also hit the 90s unusually early; the first time in 120 years of National Weather Service record-keeping that the city had topped the 90s before March 20. Those numbers do not prove heat causes any one tragedy, but they do show southern Utah is spending more time in the kind of extreme conditions that researchers are now linking to elevated mental-health risk.

SENIORS (AND OTHERS) BEWARE

The local demographics make the issue even more urgent. Washington County’s 2024 population estimate was 207,943, up 15.3% from the 2020 base, and 22.5% of county residents are now 65 or older, according to the U.S. Census Bureau. Utah public health data also shows 19.3% of St. George residents were 65 and older in 2022, while the Southwest health district was at 20.8%. Seniors are not the only group affected by extreme heat, but they are among the most vulnerable. In a fast-growing, aging region like southern Utah, the new study is a reminder that heat is not just a weather story. It is a public-health story too.