The health effects of extreme heat

A construction worker rests on grass with a safety vest over his face.

How our research is contributing to the public health response

In the United States, heat-related mortality is the number one weather-related killer—and these deaths are nearly all preventable. As global warming continues, scientists predict extreme and dangerous heat waves will be much more common.

The UW Department of Environmental & Occupational Health Sciences (DEOHS) is at the leading edge of research into how extreme heat affects people’s health. We particularly focus on those who are most vulnerable to the health risks, including farmworkers, outdoor laborers and the elderly.

Our research is also identifying new ways to help communities adapt to heat through risk communication, evidence-based policies, land-use strategies and other approaches.

Learn more about this research led by our Center for Health and the Global Environment, Collaborative on Extreme Event Resilience and the Pacific Northwest Agricultural Safety and Health Center, all part of DEOHS.

Our impact

Smoky skies over the Seattle skyline looking west to Olympic Mountains.

Climate change causing ‘indisputable’ harm to our health

5th National Climate Assessment authors include DEOHS climate experts

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Headshot of DEOHS Professor Kristie Ebi.

DEOHS Professor Kristie Ebi named 2023 AGU Fellow

American Geophysical Union recognizes Ebi for her work on health-related climate change impacts

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Joan Casey sits at a wood table outside on the UW campus with trees in the background.

Seeking sustainability and environmental justice

New DEOHS faculty member Joan Casey uses big data to analyze population-scale health problems and solutions

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Families paying in fountain with the words 'Special Feature' over the top.

The heat is on: How to protect health in extreme heat

DEOHS is collaborating with cross-sector partners to prepare for a hotter future in the Pacific Northwest

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Utility workers in cherry pickers work on electrical power lines.

These four regions of the US are hardest hit by power outages

Prolonged power outages plague regions already facing climate and social vulnerability, new study shows

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The Space Needle in the foreground with Seattle neighborhoods and a bright setting sun over Puget Sound and the Olympic Mountains in the background.

Washington state’s 2021 heat wave led to previously uncounted deaths from injury

Heat wave contributed to 159 excess injury deaths over three weeks, new study led by DEOHS faculty member shows

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In the news

The climate crisis is endangering workers
August 19, 2025 | Think Landscape | Featured: Kristie L. Ebi View

We knew increasing heat was bad for our health. A new study reveals how much.
August 1, 2025 | The Weather Channel | Featured: Kristie L. Ebi View

Hotter summers could be making us sicker in unexpected ways
July 30, 2025 | Washington Post | Featured: Kristie L. Ebi View

Federal cuts put Washington workplace safety research at risk
July 29, 2025 | Cascade PBS | Featured: Marissa Baker, Elena Austin View

1500 deaths in the recent European heatwave were due to climate change
July 9, 2025 | New Scientist | Featured: Kristie L. Ebi View