National Weather Service Forecast for: Florissant MO
Issued by: National Weather Service Saint Louis, MO
Updated: 9:01 pm CDT Jun 29, 2026
 
Tonight

Tonight: Mostly clear, with a low around 77. South wind 6 to 8 mph.
Mostly Clear

Tuesday

Tuesday: Sunny and hot, with a high near 98. Heat index values as high as 106. Southwest wind 6 to 9 mph.
Hot

Tuesday
Night
Tuesday Night: Clear, with a low around 78. South wind 5 to 7 mph.
Clear

Wednesday

Wednesday: Sunny and hot, with a high near 98. Heat index values as high as 106. Southwest wind 5 to 7 mph.
Hot

Wednesday
Night
Wednesday Night: Mostly clear, with a low around 79. South wind 5 to 8 mph.
Mostly Clear

Thursday

Thursday: Sunny and hot, with a high near 97.
Hot

Thursday
Night
Thursday Night: Partly cloudy, with a low around 78.
Partly Cloudy

Friday

Friday: A 40 percent chance of showers and thunderstorms after 1pm.  Mostly sunny, with a high near 95.
Sunny then
Chance
T-storms
Friday
Night
Friday Night: A 20 percent chance of showers and thunderstorms after 1am.  Partly cloudy, with a low around 77.
Partly Cloudy
then Slight
Chance
T-storms
Lo 77 °F Hi 98 °F Lo 78 °F Hi 98 °F Lo 79 °F Hi 97 °F Lo 78 °F Hi 95 °F Lo 77 °F

Extreme Heat Warning
 

Tonight
 
Mostly clear, with a low around 77. South wind 6 to 8 mph.
Tuesday
 
Sunny and hot, with a high near 98. Heat index values as high as 106. Southwest wind 6 to 9 mph.
Tuesday Night
 
Clear, with a low around 78. South wind 5 to 7 mph.
Wednesday
 
Sunny and hot, with a high near 98. Heat index values as high as 106. Southwest wind 5 to 7 mph.
Wednesday Night
 
Mostly clear, with a low around 79. South wind 5 to 8 mph.
Thursday
 
Sunny and hot, with a high near 97.
Thursday Night
 
Partly cloudy, with a low around 78.
Friday
 
A 40 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 95.
Friday Night
 
A 20 percent chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 77.
Independence Day
 
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 95.
Saturday Night
 
A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 77.
Sunday
 
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 93.
Sunday Night
 
A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 75.
Monday
 
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 90.

 

Forecast from NOAA-NWS for Florissant MO.