Rapid City hits all-time high of 112°F as heat wave persists
At least 40 million people across the central and southern United States remained under extreme heat warnings on Sunday as a heat dome continued to trap dangerously high temperatures for a second consecutive day, according to the National Weather Service.
Heat indexes well above 100°F (38°C) stretched from Minnesota down to Mississippi and extended west into southern California and Nevada, the NWS reported. Parts of the Southwest were expected to see highs of 120°F (49°C).
“It’s extraordinarily hot,” said Pete Miller, an outreach manager for the homeless services network Threshold CoC in Omaha, Nebraska. “We’re seeing a lot of people who are exhausted, drained by the heat in a way that is really dangerous.”
Miller added that humidity was exacerbating the conditions, noting that standing outside for 30 seconds caused drenching and that the situation would persist through the night.
Rapid City, South Dakota, reported an all-time high of 112°F on Saturday. A horse race scheduled at Canterbury Park in Shakopee, Minnesota, was canceled on Sunday because of the heat.
Bob Oravec, an NWS meteorologist, said the sweltering conditions were the result of another heat dome, a phenomenon in which atmospheric conditions trap heat, accentuating and prolonging already high temperatures.
“Right now, it’s affecting a lot of people right in the middle of the country,” Oravec said. “The core of the heat sinks southward by early next week.”
The moist air associated with the heat dome was also producing other volatility, including the risk of severe thunderstorms, flash flooding and hail around the Great Lakes on Sunday, with the potential for heavy storms to move east in the coming days, Oravec said.
“If you have a heat dome in one part of the country, you’ll have a different corresponding weather in another part,” he said. “It’s all related.”
Temporary relief is expected for the central United States toward the middle of the week, but high temperatures could return by the weekend, Oravec said.
Authorities warned that children, older adults, and people with certain medical conditions are especially at risk of serious heat-related illnesses, including heat stroke or death. Officials recommend seeking air conditioning or cooling centers, drinking enough water, and limiting time in direct sun.
The extreme heat is part of a broader pattern. The continental United States endured its second-hottest first half of the year on record in 2026, according to the National Centers for Environmental Information. The Guardian reported that extreme heat events are increased and exacerbated by the climate crisis, which results from the burning of fossil fuels such as gasoline, oil, and coal.