St. Louis is getting the classic spring fake-out on Friday, May 1, 2026: a crisp start near 46°F under clear skies, followed by a steady climb into the low to mid 60s by afternoon. Sunshine will do most of the heavy lifting, with only a light north breeze and a slim chance of a shower late tonight after 10 p.m. The real headline, though, is the quick warmup barreling in for the weekend and early next week, with highs jumping into the 70s by Sunday and reaching the low 80s by Monday, along with rising humidity and growing odds for showers and thunderstorms.
Afternoon and Tonight
Expect a bright, blue-sky kind of Friday, with highs near 64°F and north winds around 8 mph keeping things feeling fresh rather than hot. Most of the day and evening stay dry, and the National Weather Service outlook suggests only a low-end chance of showers sneaking in after 10 p.m. Overnight lows dip to around 45°F, so it will be a good night to keep a light jacket handy.
Weekend Outlook
Saturday backs off the warmth just a touch, with a high near 62°F. There is a slight chance of showers before 7 a.m., but those should exit quickly, leaving mostly sunny skies for the rest of the day. Saturday night turns mostly clear and cool, with lows around 42°F. By Sunday, the weather flips the switch: highs jump to around 76°F and winds swing to the southwest, pulling in more humid air. That warmer, stickier setup will lay the groundwork for more unsettled weather not far behind.
Early Next Week
The returning warm and humid air on Sunday gives Monday, May 4, a serious boost, with afternoon highs expected to reach about 81°F. After that, rain and thunderstorm chances ramp up Monday night into Tuesday, May 5. Forecasters at the National Weather Service describe a warm-to-wet pattern developing, with storms capable of brief heavy downpours and localized impacts. Widespread severe weather is not currently anticipated, but it is worth keeping tabs on forecast updates Monday, especially if you have travel plans or outdoor events lined up for late Monday into Tuesday.
Plan Ahead
Enjoy the mostly dry, comfortable weather through Saturday, then be ready for a quick jump to much warmer and more humid conditions on Sunday. With the potential for storm-related hiccups Monday and Tuesday, checking the latest from the National Weather Service and your go-to weather app before heading out early next week could save you from getting caught in a surprise shower or thunderstorm.
