U.S., especially the South, could see heat-index temps above 125 degrees by 2053; see how your area may fare

Predicted days with a heat index of 100° F. (Map by The Washington Post; data from First Street Foundation)

"An 'extreme heat belt' reaching as far north as Chicago is taking shape, a corridor that cuts through the middle of the country and would affect more than 107 million people over the next 30 years, according to new data on the country's heat risks," Denise Chow and Nigel Chiwaya report for NBC News. "The report, released Monday by the nonprofit research group First Street Foundation, found that within a column of America's heartland stretching from Texas and Louisiana north to the Great Lakes, residents could experience heat index temperatures above 125 degrees Fahrenheit by 2053." The heat index includes temperature and humidity to create a more accurate measure of how hot it feels outside, rather than measuring temperature alone.

Counties expected to gain the most days with a heat index above 125° F. (NBC News map)

Heat will become an increasing threat as climate change worsens. "A Washington Post analysis of the group’s data found that today’s climate conditions have caused an estimated 46 percent of Americans to endure at least three consecutive days of 100-plus degree heat, on average, each year. Over the next 30 years, that will increase to 63 percent of the population," the Post reports. "Nowhere is the danger more widespread than in the South, where global warming is expected to deliver an average of 20 extra days of triple-digit heat per year. In some southern states, such as Texas and Florida, residents could see over 70 consecutive days with the heat index topping 100 degrees Fahrenheit.

See what the report predicts for your community with the Post's interactive map. It shows how many days the heat index is expected to top 100 degrees in 2023, in contrast with 2053.