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It’s Not Just You — Summers Are Getting Hotter. And Longer.

person indoors with head in hand sitting in front of a fan

July 16, 2024

UHC researchers have spent much of their careers studying the effects of heat on population health. This summer explains why. New climate metrics from the Big Cities Health Indicators data platform show us that extreme heat we are experiencing is the new normal, following a steady and steep increase in the number of heat waves we experience each summer. UHC researchers also noted an increase in the duration of seasonal summer heat: the seasonal average being 30 days longer than it was decades ago. In other words, summers are getting hotter and longer.

Extreme heat can have immediate effects on people’s health, but the change in conditions has affected ecosystems as well, increasing the duration of allergy seasons, droughts and wildfire seasons, and increasing people’s exposure to mosquito- and tick-borne diseases. People with chronic diseases, children, and elderly people are more susceptible to the effects of heat, and are advised to “stay cool in an air-conditioned area.” But what if you can’t afford to cool your indoor space adequately?

This is an urgent concern, says UHC Affiliate Dr. Leah Schinasi, whose recent review article, “Surviving indoor heat stress in United States: A comprehensive review exploring the impact of overheating on the thermal comfort, health, and social economic factors of occupants,” recently received attention from local and national media.

"As we know, many lower-income households do not have adequate access to air conditioning," Dr. Shinasi told ABC News. "Even if they do have access, they're often unable to afford to use it as much as needed because of the enhanced energy costs that come with using air conditioning."

Renters, especially, might not be able to control the temperature inside their homes. While most states require landlords to provide heat, few states or cities require landlords to cool their properties, putting renters at risk. As Dr. Schinasi told Vox, “It can actually get hotter indoors than outside, and this is a really important environmental justice issue.”

Dr. Schinasi and team recommend a multi-pronged approach to mitigating the impacts of indoor heat, including using adaptive models to assess risk, revising building codes, and financial assistance for vulnerable residents.

It’s important to stress that heat is a hazard to people’s health.” Dr. Schinasi added in the Philadelphia Inquirer. “Historically, it hasn’t been recognized as an environmental hazard.”