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St Clair County, MO Weather Forecast
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St Clair County Weather Forecast
| THIS AFTERNOON | TONIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY | SATURDAY NIGHT |
 |  |  | |  |  | |  | | | | |
| Chance of Showers | Mostly Clear | Sunny | Clear | Chance of T-Storm | Chance of T-Storm | Chance of T-Storm | Chance of Showers | Chance of T-Storm | Chance of T-Storm | Chance of T-Storm | Chance of Showers |
| Hi: 99°FHi: 37°C | Lo: 75°FLo: 24°C | Hi: 100°FHi: 38°C | Lo: 79°FLo: 26°C | Hi: 99°FHi: 37°C | Lo: 69°FLo: 21°C | Hi: 85°FHi: 29°C | Lo: 65°FLo: 18°C | Hi: 89°FHi: 32°C | Lo: 69°FLo: 21°C | Hi: 90°FHi: 32°C | Lo: 69°FLo: 21°C |
| POP: 20% | POP: 70% | POP: 100% | POP: 70% | POP: 30% | POP: 40% | POP: 50% | POP: 20% | POP: 20% |
POP = Probability of Precipitation.
Weather Outlook Updated: 128 PM CDT Mon Sep 07 2026 
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Issued: 148 PM CDT Mon Sep 7 2026
Key Messages
- An Extreme Heat Warning is in effect through Tuesday evening for counties west of Highway 65. Maximum afternoon heat index values around 105+.
- Hot and dry conditions are worsening drought and increasing fire danger. Above average temperatures are likely most of this week with highs in the 90s to around 100 Tuesday and Wednesday. Additional heat headlines may be warranted.
- There is a 60-90% chance of showers and thunderstorms Wednesday evening into Thursday and includes a marginal ris...