St. Louis is baking today under mostly sunny skies with a high near 94°F, but heat index values climbing as high as 105°F mean it’ll feel like deep summer in the Gateway City — plan outdoor time for early morning or after sunset. Patchy fog and lingering Canadian wildfire smoke are cutting visibility and air quality through midday, especially near the Mississippi River, before a weak warm front pushes northeast this afternoon.
Today’s Setup
The National Weather Service St. Louis office has a Heat Advisory in effect as pooled dewpoints combine with sunshine to push heat index values to 100-108°F. Winds stay light out of the southeast around 2 mph, so there’s little relief — the air just sits heavy over the metro.
Best Window To Be Outside
Mornings before 10 AM CT are your best bet, before temperatures peak. Forest Park trails, the Gateway Arch grounds, and the Riverfront Trail will all feel more bearable at sunrise than by mid-afternoon. Save yard work, dog walks, and jogs for early, or wait until after 7 PM CT as things ease toward tonight’s low near 79°F.
Heat, Fog, And Overnight Storm Chances
Tonight stays mostly clear and muggy with a low around 79°F. The Area Forecast Discussion flags the best shower and thunderstorm chances — including a conditional risk of a marginally severe storm and locally heavy rain — overnight into Tuesday morning, mainly north of I-70. Tuesday itself turns even hotter, with a high near 96°F and heat index values again near 105°F. Wednesday finally brings relief with a high near 85°F and a drier stretch through Thursday.
What To Wear Or Bring
Light, breathable clothing and constant hydration are non-negotiable today. Keep a Yeti rambler water bottle or insulated water jug 1 gallon topped off, and if you’re headed to a ballpark or park picnic, a rolling cooler with wheels makes hauling drinks and ice much easier in this heat.
Cardinals, Concerts, And Tailgating
The St. Louis Cardinals host the Arizona Diamondbacks at Busch Stadium on July 23 — expect warm, humid tailgating conditions typical of late-July St. Louis, so hydrate before first pitch. Gear up with a St. Louis Cardinals jersey or St. Louis Cardinals fitted cap, and grab tickets on SeatGeek or tickets on StubHub. Tomorrow night, July 21, Usher Raymond & Chris Brown bring The R&B Tour to The Dome at America’s Center — a Usher Raymond & Chris Brown t-shirt or Usher Raymond & Chris Brown hoodie makes a great show-night layer once the AC kicks in.
Tonight’s Dinner Idea
With this kind of heat, skip the stove — a cold Thai noodle salad or smoothie bowls hit the spot tonight. A high-powered blender and insulated tumbler 30oz make quick work of either. Need ingredients? You can order groceries on Amazon and have everything for tonight’s dinner delivered to your door. Once it cools off Wednesday, it’s a good night to try the smoke tri-tip guide instead.
Next Few Days
Expect one more hot, humid day Tuesday before a much cooler, drier pattern settles in Wednesday through Thursday — ideal for mowing the lawn or finally getting outside without heat index warnings. Cool off in the meantime with a 2-Person Intex Floating Lounge for the pool or river.
