St. Louis is waking up to a cloudy, muggy Thursday, with temperatures hovering near 75°F (24°C) and relative humidity around 94 percent. Showers and thunderstorms are likely to fire up after 11 a.m. on Thursday, July 16, 2026, with the most active period expected in the early to mid-afternoon. If you have outdoor plans, keep the umbrella close; brief heavy downpours and frequent lightning could cut things short in a hurry.
Afternoon Storms Likely
Forecasters expect showers and thunderstorms to become more widespread from midday into the mid-to-late afternoon, with roughly a 60 percent chance of rain and the greatest storm coverage south of I-70. According to NWS St. Louis, storms may produce brief heavy rain and lightning. Temperatures should peak in the low 90s, then dip a few degrees where stronger cells pass through.
The same forecast discussion points to a return of heat heading into the weekend, with highs in the low-to-mid 90s and heat index values potentially reaching around 100 to 105°F on the hottest afternoons.
Weekend Outlook
A weak boundary may try to slide through late Saturday into Sunday, which keeps a small chance of late-afternoon pop-up storms in the weekend mix. The warmer pattern looks most noticeable on Saturday and again Monday, when the combination of heat and humidity could make it feel several degrees hotter than the actual air temperature.
For background on the region’s recent heavy-rain setup, see our earlier update last Saturday on the recent heavy-rain setup.
Plan For The Commute
Midday and afternoon travel could get messy at times as pockets of heavy rain move through. Build in extra time for errands or events and be ready for brief drops in visibility when storms roll overhead. Avoid driving through standing water, secure loose outdoor items, and remember that lightning is the main short-term hazard for anyone outside.
Keep wireless alerts turned on and have a quick plan for where to go if thunder starts rumbling while you are at work sites, ballfields, or outdoor gatherings.
There are no watches or warnings in effect right now for Missouri or Illinois, but conditions could change quickly this afternoon. Keep an eye on updated forecasts and local alerts through the day. We will relay any changes or new advisories as they come in.
