Extreme Heat Days

In 2021, 92% of Southerners experienced at least 5 extreme heat days, and 64% experienced 15+ extreme heat days.

Number of extreme heat days (100°F Heat Index)

May - September 2021

Source: CDC/ NASA. Notes: Data not available for Hawaii or Alaska.

Hot days that are more humid actually feel hotter. The National Weather Service regularly reports the “heat index” – which is the temperature that the human body experiences on hot and humid days. A heat index of 100°F is considered an extreme heat day. Older adults, young children, and pregnant women can experience damage to vital organs and even die from extreme heat.¹

Southerners are more likely to experience extreme heat days. In 2021, 92% of Southerners (versus 61% of non-Southerners) were exposed to 5+ days of extreme heat, and 64% of Southerners (versus 28% of non-Southerners) were exposed to 15+ days of extreme heat. In Arkansas, Florida, Louisiana, and Mississippi, 99-100% of the population experienced 15+ days with heat indexes of 100°F.

Air conditioning is critical for keeping vulnerable people safe during extreme heat days. But lower-income households and renters are less likely to have air conditioning, even in the South where air conditioning is more widely available.² Families with lower incomes also tend to live in older buildings with poor insulation leading to higher utility bills. The Inflation Reduction Act includes substantial funding that can be used for home weatherization, but only via tax credits for homeowners. Ensuring renters have homes that protect them from extreme heat and have affordable utility bills will be an important focus for communities and policymakers.³

1. “About Extreme Heat”. CDC. https://www.cdc.gov/disasters/extremeheat/heat_guide.html

2. “As extreme heat grips the globe, access to air conditioning is an urgent public health issue”. Mann, Schuetz. Brookings. July, 2022. https://www.brookings.edu/blog/the-avenue/2022/07/25/as-extreme-heat-grips-the-globe-access-to-air-conditioning-is-an-urgent-public-health-issue/

3. “The U.S. needs better, more accessible home weatherization programs”. Mann, Schuetz. Brookings. October, 2022. https://www.brookings.edu/blog/the-avenue/2022/10/10/the-u-s-needs-better-more-accessible-home-weatherization-programs/