40 Million Under Heat Warnings
At least 40 million people across central and southern parts of the United States experienced extreme heat warnings on Sunday. High temperatures and severe humidity affected large areas for the second consecutive day. Heat indexes surpassed 100 degrees Fahrenheit (38 Celsius) from Minnesota to Mississippi, stretching west into southern California and Nevada. The Southwest anticipated highs reaching 120 degrees Fahrenheit (49 C), the National Weather Service reported.
Heat Dome Phenomenon
Meteorologists attributed the intense heat to a heat dome, where atmospheric conditions trap heat, heightening and prolonging already elevated temperatures. Pete Miller from Threshold CoC, a homeless services network, commented on the situation while distributing water in Omaha, Nebraska: “It’s extraordinarily hot. People seem exhausted and dangerously drained.”
The humidity was severe: “Standing outside for 30 seconds leaves you drenched, and this persists throughout the night,” Miller said.
Record Highs and Disruptions
Rapid City, South Dakota, experienced a record high of 112 degrees Fahrenheit (44 C) on Saturday. The extreme heat led to the cancellation of a horse race at Canterbury Park in Shakopee, Minnesota.
Widespread Effects
“Many people in the country’s center are affected,” said Bob Oravec, a meteorologist with NWS. By early next week, heat’s core will move southward. The moist air is causing volatility, including thunderstorms, flash flooding, and hail around the Great Lakes. Heavy storms are predicted to move east soon. Oravec explained, “If a heat dome impacts one area, different weather conditions occur elsewhere.”
Temporary Relief Expected
The central U.S. may see relief in midweek, although high temperatures might return by the weekend. Authorities caution that children, older adults, and individuals with certain medical conditions face severe risks like heat stroke. Experts advise using air conditioning, staying hydrated, and minimizing direct sun exposure.
Temperature Records
In 2026, the continental U.S. had the second-hottest first half of the year on record, according to the National Centers for Environmental Information’s tracking of average temperatures.