ST. LOUIS | St. Louis readers should plan for a hot and sunny 28 June, with the National Weather Service forecast calling for a high near 94°F and heat-index values as high as 109°F.
What the forecast shows
The forecast calls for sunny conditions, south wind around 6 to 9 mph and a hot afternoon. Tonight is expected to be mostly clear with a low near 76°F and continued heat-index values that may feel warmer than the posted air temperature.
This is a city weather brief, not a replacement for any severe weather alert or heat warning that may be issued separately. Conditions should be checked again before travel, outdoor work, school activities, sports, construction, public events or long exposure to pavement and direct sun.
Why it matters
Heat-index values near 109°F can create meaningful health risk. Outdoor workers, older adults, children, athletes, people without dependable cooling and people attending outdoor events should plan for water, shade, rest and cooling access.
Urban heat can feel worse on parking lots, roadways and construction areas. In St. Louis, the combination of summer humidity, major corridors and outdoor gatherings can turn a routine sunny forecast into a day that requires deliberate planning.
What remains uncertain
The day’s exact heat impact will depend on humidity, cloud cover, wind, timing and any updated National Weather Service alert. A forecast can change as new observations are added.
What to watch next
Readers should watch for updated National Weather Service heat products, local cooling-center information, event guidance and any public-safety messages related to outdoor exposure.
Additional Reporting By: National Weather Service; NOAA