Weather World
St Charles County, MO Weather Forecast
Quick Weather Clicks
Settings
Sun & Moon
St Charles County Weather Forecast
| TONIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY | SATURDAY NIGHT | SUNDAY | SUNDAY NIGHT | MONDAY | MONDAY NIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY |
 |  |  | | |  | | | |  | |  |
| Chance of T-Storm | Sunny | Partly Cloudy | Mostly Sunny | Partly Cloudy | Chance of T-Storm | Chance of T-Storm | Chance of T-Storm | Chance of T-Storm | Partly Sunny | Partly Cloudy | Partly Cloudy |
| Lo: 71°FLo: 22°C | Hi: 95°FHi: 35°C | Lo: 71°FLo: 22°C | Hi: 95°FHi: 35°C | Lo: 71°FLo: 22°C | Hi: 91°FHi: 33°C | Lo: 69°FLo: 21°C | Hi: 81°FHi: 27°C | Lo: 61°FLo: 16°C | Hi: 75°FHi: 24°C | Hi: 80°FHi: 27°C Lo: 59°FLo: 15°C | Hi: 80°FHi: 27°C Lo: 59°FLo: 15°C |
| POP: 20% | POP: 20% | POP: 50% | POP: 60% | POP: 50% |
POP = Probability of Precipitation.
Weather Outlook Updated: 608 PM CDT Thu Sep 17 2026 
St Charles County Radar Loop
Use the map search tool if you want to place a location marker on the radar map...
St Charles County Weather Map
St Charles County Quick Facts
St Charles County Forecast Discussion
Meteorlogic Glosserator
Instant definitions for any meteorological term.
Instant definitions for any meteorological term.
Issued: 654 PM CDT Thu Sep 17 2026
Key Messages
- Unusually hot and humid conditions will persist through at least Saturday, with the potential to linger into Sunday in some areas. Heat relief is expected early next week.
- A 20-30% chance of showers and weak thunderstorms exists this afternoon and again tomorrow afternoon. However, more substantial (60-80%) rain chances arrive late Saturday through Monday.
Aviation
/00Z TAFS THROUGH 06Z SATURDAY/... Issued at 639 PM CDT Thu Sep 17 2026
This afternoon`s convection has largely dissipated....