Sioux Falls, South Dakota – Residents across southeastern South Dakota will face several hours of oppressive heat Monday, with heat index values climbing above 100 degrees in many communities before noticeably dropping by mid-to-late afternoon as cooler, drier air pushes into the region. The highest apparent temperatures are expected around midday and early afternoon, making outdoor work and recreation increasingly hazardous before conditions improve later in the day.
According to the National Weather Service in Sioux Falls, heat index values will steadily fall beginning during the mid-to-late afternoon as a cold front ushers in less humid air. While relief arrives first across eastern South Dakota, portions of northwest Iowa will remain hotter longer before the front clears the area.
Communities including Sioux Falls, Mitchell, Madison, Brookings and Yankton are expected to experience heat index values ranging from the upper 90s to more than 105 degrees during the peak of the day. Sioux City could reach a heat index of around 108 degrees during the afternoon, while Yankton may peak near 109 degrees. Lake Andes, Sioux Center, Spencer, Storm Lake and Worthington are also expected to see apparent temperatures above 100 degrees.
Anyone spending time outdoors should drink plenty of water, take frequent breaks in air-conditioned locations, and avoid strenuous activity during the hottest part of the afternoon. Never leave children or pets inside parked vehicles, where temperatures can become life-threatening within minutes.
Conditions become much more comfortable Monday evening, and the remainder of the week is expected to feature lower humidity with afternoon highs generally in the lower 80s. Additional updates will be issued if any heat-related advisories become necessary.
