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Olmsted, IL Weather Forecast
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Olmsted Weather Forecast
| THIS AFTERNOON | TONIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY | SUNDAY |
 |  | | |  |  |  | | | | | |
| Sunny | Clear | Sunny | Mostly Clear | Chance of T-Storm | Chance of T-Storm | Clearing | Mostly Clear | Mostly Sunny | Mostly Clear | Mostly Clear | Sunny |
| Hi: 89°FHi: 32°C | Lo: 65°FLo: 18°C | Hi: 91°FHi: 33°C | Lo: 71°FLo: 22°C | Hi: 85°FHi: 29°C | Lo: 69°FLo: 21°C | Hi: 89°FHi: 32°C | Lo: 59°FLo: 15°C | Hi: 69°FHi: 21°C | Hi: 61°FHi: 16°C Lo: 41°FLo: 5°C | Hi: 61°FHi: 16°C Lo: 41°FLo: 5°C | Hi: 71°FHi: 22°C |
| POP: 90% | POP: 60% | POP: 50% |
POP = Probability of Precipitation.
Weather Outlook Updated: 237 PM CDT Mon Oct 12 2026 
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Issued: 134 PM CDT Mon Oct 12 2026
Key Messages
- Record-breaking high temperatures and elevated humidity will bring heat index values in the 90s to low 100s on Tuesday.
- Widespread showers and thunderstorms with coverage of 70 to 100% are forecast Wednesday into Thursday morning.
- Lingering shower and thunderstorms chances with 50 to 70% coverage are forecast Thursday across northern parts of southeast Missouri, southern Illinois, and Evansville Tri- State region.
- A strong cold front will pass Thursday night, bringing a return of dry...