St. Louis, Missouri – Temperatures will surge across Missouri and Illinois by Friday afternoon, climbing 10 to 15 degrees above normal and bringing early-season heat alongside increasing thunderstorm chances.
According to the National Weather Service Climate Prediction Center, there is a 70 to 80 percent probability of above-normal temperatures across the region through early next week. Eastern Missouri and southwestern Illinois, including St. Louis, Belleville, and Springfield, sit in a favorable zone for sustained warmth.
St. Louis is expected to reach the upper 80s by Saturday between 2 p.m. and 6 p.m., with similar conditions extending east along I-64 into Illinois. Cities like Springfield and Champaign will see highs in the low to mid-80s, while areas along I-55 warm quickly under partly sunny skies.
By late afternoon into the evening, increasing Gulf moisture will trigger scattered showers and thunderstorms across both states. Storms may produce brief heavy rain, lightning, and wind gusts over 40 mph, especially along I-70, I-55, and I-64, potentially impacting evening travel.
Residents should stay hydrated, remain weather-aware during the late-day storm window, and prepare for brief disruptions during peak travel hours. This pattern will persist through the weekend into early next week, with additional advisories likely as heat and storm chances continue.
