St. Louis woke up early Tuesday, June 30, 2026 to clear skies and air that already feels like a wet blanket. At 5:35 a.m. CDT it was about 77°F with dew points near 73°F, the kind of humidity that guarantees the rest of the day will be sticky and uncomfortable. Forecasters say this is just the opening act of a heat wave that will park over the metro through the July 4 holiday weekend.
The National Weather Service has placed the St. Louis metro under an Extreme Heat Warning through 10 p.m. CDT Friday, July 3, 2026, citing dangerous heat and humidity with heat index values expected to climb above 109°F. According to the National Weather Service, sunny afternoons will send highs to around 98°F today and Wednesday.
When It Will Be Worst
The most punishing stretch will hit late morning through late afternoon, roughly from 11 a.m. to 6 p.m., when heat index readings are likely to push into the 105 to 110°F range. Overnight lows will only fall into the upper 70s, which means very little relief even after sunset through Friday.
If you work outside, try to shift the heaviest tasks into the early morning or evening, take frequent water breaks, and keep an eye out for headache, dizziness, heavy sweating, or nausea, which can be signs of heat exhaustion.
Where To Cool Off
Residents without reliable air conditioning have options, but they may need a plan. Neighborhood cooling centers and assistance programs are available through the city directory, and you can call 2-1-1 for immediate help and referrals.
For specific sites and hours, check the City of St. Louis cooling center list at City of St. Louis.
Looking Ahead
The ridge of high pressure driving this heat is expected to weaken late in the week, which should allow a few scattered afternoon storms to pop up by Friday and Saturday. Those storms may bring brief, localized cooling but are not expected to break the heat across the region.
The Fourth of July is still on track to be hot and humid, with highs in the mid 90s and only spotty shower chances. If you are planning parades, barbecues, or fireworks viewing, build in shade, easy access to air conditioning, and lots of water. Keep an eye on updated forecasts and check in on neighbors, older relatives, and anyone who may not have air conditioning.
