St. Louis Weather Reaches Extreme Heat Alert Status as Heat Dome Sweeps Across Midwest

St. Louis weather is entering dangerous heat territory, with extreme heat alerts now in effect for the city and surrounding areas. Upper 90s temperatures are forecast, though the real danger comes from humidity-driven heat index values that will feel significantly hotter across the region and beyond.

A Heat Dome Affects Over 100 Million Americans

An expansive heat dome stretching from the Southwest through the Plains and into the Upper Midwest is bringing record-breaking temperatures to much of the nation. At least seven major cities are expected to reach triple-digit highs, including Las Vegas at 112 degrees, Phoenix at 109 degrees, and Rapid City, South Dakota at 105 degrees. Denver's forecast high of 102 degrees would surpass its July 26 record of 100 degrees, originally set in 1910.

The St. Louis area joins Memphis, Minneapolis, Omaha, and Springfield, Missouri under extreme heat warnings. While St. Louis itself is forecast for upper 90s, the surrounding region and other affected areas will see temperatures in the triple digits. Cities including Omaha, Denver, Dallas, and Kansas City are all expected to exceed 100 degrees.

Heat Index Values Pose the Greatest Risk

From Texas to the Upper Midwest, high humidity amplifies the danger significantly. Heat index values—the temperature the body perceives when accounting for humidity—are expected to range from 105 to 115 degrees across a broad area, with some locations potentially feeling even hotter. In Kansas City, the feels-like temperature on Monday is forecast to reach 107 degrees, while Dallas could feel like 107 and Omaha like 110 degrees.

Overnight hours will provide minimal relief. Temperatures in Phoenix and Las Vegas are only expected to drop to around 90 degrees Sunday night, while cities such as Dallas, Kansas City, and Omaha will only see lows near 80 degrees. A cold front is expected to bring some cooler weather to the Upper Midwest early in the week, but dangerous heat will persist across much of the central and southern United States through at least Monday, with portions of the South and Southwest experiencing extreme conditions beyond that timeframe.