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Reports of Poor Mental Health More Likely on Hotter Days

April 08, 2020

The average American adult is more likely to report poor mental health on days with higher temperatures, according to a study published online in PLOS One.

“The promotion of mental health has—for the first time—been included in the United Nations Sustainable Development Agenda under goal number 3 (Good Health and Well-being) to be reached by 2030. In a rapidly warming world, temperature increases pose a challenge to achieving that goal,” wrote researchers from the department of agricultural and applied economics at the University of Georgia, Athens. “Our study attempts to gauge the magnitude of that challenge by quantifying the effect of temperature on self-reported mental health.”

The study looked at individual mental health data for more than 3 million Americans between 1993 and 2010 and matched it with historical daily weather information.

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Compared with a temperature range between 60°F and 70°F, hotter days in the past month increased the probability of reporting days of bad mental health as well as mental distress. Cooler days, however, decreased the probability, according to the study. A potential mechanism of the beneficial effect of cooler temperatures could be better sleep, researchers wrote. 

The study also found that the beneficial effect of cooler days is immediate. Hotter days, on the other hand, matter most after 10 consecutive days. 

Researchers also estimated the economic costs of climate change by monetizing the effect of temperature increases on individual mental health. According to the study, people were willing to pay $2.60 to $4.60 to avoid an additional hot day in the past month.

“It would be interesting for future studies to shed light on how community level factors mediate the effects of climate change on individual mental health,” researchers wrote, “and design policies accordingly.” 

—Jolynn Tumolo 


Li M, Ferreira S, Smith TA. Temperature and self-reported mental health in the United States. PLOS One. 2020 March 25;15(3):e0230316.

Heat takes its toll on mental health [press release]. San Francisco, California: PLOS; March 25, 2020.

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