February 28, 2023

Studies have shown that heat waves during the summer contribute to an increase in shootings in the U.S. When the thermometer soars, more people are outdoors for longer periods of time and tempers can flare.

Now a team led by Vivian Lyons, a researcher at the UW School of Social Work’s Social Development Research Group, has linked above-average temperatures at any time of the year with an increased risk of shootings. The interdisciplinary study, the largest to date on the issue, was conducted with data from 2015-2020.

Lyons and her colleagues analyzed 100 U.S. cities reporting the highest number of firearm incidents. During a six-year period, there were 7,973 shootings correlated to above-average temperatures – or nearly 7% of the total. Although gun violence was highest during the hottest days, three-fourths of the shootings linked to increased heat were on days that were only moderately above average. (Shootings were classified as those in which at least one person was killed or injured; suicides were not included.)

“We saw a consistent overall relationship between temperature and a higher risk of shootings,” said Lyons. “Knowing that firearm violence is more likely to happen on hotter days, regardless of the season, can help inform violence-prevention efforts in the future.”

The study underscores the importance of exploring heat-mitigation strategies as tools to reduce shootings. This might include deploying more resources on warm days, not just on the hottest days, to be better prepared for a spike in gun violence.

Gun violence disproportionately affects areas that have experienced racial and economic inequality in built environments and housing discrimination. These neighborhoods have more abandoned buildings and vacant lots and less green space, so residents often experience disproportionate exposure to heat and other effects of climate change. Increasing tree cover or creating small local parks are ways to cool urban temperatures and make neighborhoods feel safer and more livable.

Lyons joined the School of Social Work in 2022. She received a PhD in epidemiology from the University of Washington where she researched interpersonal violence, firearms and translational research, and recently completed post-doctoral studies at the University of Michigan’s Department of Health Behavior and Health Education.

Read more about the study:

JAMA Open Network 

The Guardian (December 16, 2022)