STORY: It’s still weeks before the start of summer, but temperatures in parts of Texas have already reached record highs. On Wednesday afternoon, heat in Austin reached a daily record high of 99 degrees Fahrenheit.

Sweltering heat more commonly seen in the throes of summer than in the spring was making an unwelcome visit this week to a large portion of the U.S. – from the Dakotas to Texas and other parts of the South – and putting millions of Americans on alert for potentially dangerous temperatures.