Climate change fuels record-breaking late summer heat in the eastern U.S.

This week, approximately 120 million people across the eastern half of the United States will face heat conditions made at least three times more likely by climate change. Forecasts predict high temperatures will approach or even surpass historical records in multiple cities from the Midwest to the East Coast. Elevated humidity will intensify the heat, which could push heat indices to 115°F in certain areas.

Note: This event may continue beyond September 1, 2024. Use the Global Climate Shift Index map to stay updated on heat in your region.

How unusual is the forecasted heat?

• Another intense heat dome is affecting millions of people across the eastern half of the United States, bringing some of the highest temperatures of the summer.

• Risky heat conditions — marked by record and near-record high temperatures, daytime heat indices of 105°F to 115°F, and hot nighttime temperatures in the mid 70’s to 80°F — will affect states from Missouri to Maryland, and major metropolitan areas including Chicago, Milwaukee, St. Louis, Indianapolis, Nashville, Charlotte, Atlanta, and Washington D.C.

• This “major to extreme heat”, as projected by the National Weather Service’s HeatRisk index, will pose a heat health risk to anyone without access to adequate cooling and/or hydration, including healthy adults.

• Among the most vulnerable to extreme heat are young children and babies. Since May at least 27 children have died in hot cars in the United States, according to Kids and Car Safety. Since 1990, at least 1,109 children have died in hot cars, and at least another 7,500 have suffered heat-related injuries.

How has climate change influenced this heat?

• From August 27-30, 76.6 million people across 19 states from Mississippi to Pennsylvania,  will experience at least one day with a Climate Shift Index (CSI) level of 5. 

  • A CSI level of 5  indicates that human-caused climate change made this extreme heat at least five times more likely, signifying an exceptional event driven by carbon pollution.

• Over the entire period, nearly 120 million people from the Midwest to the East Coast will experience at least one day with CSI level 3.

How do we know climate change is influencing this heat?

The Climate Shift Index uses peer-reviewed methodology to estimate how climate change has increased the likelihood of a particular daily temperature. It can be run using historical or forecast temperatures.

Using computer models, we compared the likelihood that these temperatures would occur in a world without carbon emissions released by humans, versus in today's world with decades of carbon emissions building up in the atmosphere. This is an established scientific method to determine how much climate change has or has not affected individual extreme weather events.

For this analysis, temperatures come from the National Center for Environmental Prediction’s Global Forecast System.

To request an interview with a Climate Central scientist, please contact Abbie Veitch at aveitch@climatecentral.org 

Reporting resources

Until carbon emissions end, heat waves everywhere will continue to become hotter and more dangerous. Explore quick facts and local analyses on the links between climate change and extreme heat in:

• Climate Central’s Extreme Weather Toolkit: Extreme Heat

• World Weather Attribution’s guide to reporting on extreme heat and climate change

• Yale Climate Connections’ summary of the connection between heat waves and climate change.

• Potential Energy’s Guide to Reporting on Unnatural Disasters