Ottawa, IL Weather Forecast
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Ottawa Weather Forecast
| THIS AFTERNOON | TONIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY | SATURDAY NIGHT | SUNDAY | SUNDAY NIGHT |
| Partly Cloudy | Chance of T-Storm | Chance of T-Storm | Chance of Showers | Clearing | Clear | Sunny | Chance of Showers | Chance of Showers | Chance of Showers | Chance of Showers | Chance of Showers |
| Hi: 85°FHi: 29°C | Lo: 70°FLo: 21°C | Hi: 81°FHi: 27°C | Lo: 65°FLo: 18°C | Hi: 80°FHi: 27°C | Lo: 55°FLo: 13°C | Hi: 80°FHi: 27°C | Lo: 65°FLo: 18°C | Hi: 85°FHi: 29°C | Lo: 65°FLo: 18°C | Hi: 81°FHi: 27°C | Lo: 61°FLo: 16°C |
| POP: 50% | POP: 80% | POP: 20% | POP: 20% | POP: 40% | POP: 40% | POP: 40% | POP: 40% |
POP = Probability of Precipitation.
Weather Outlook Updated: 120 PM CDT Tue Sep 08 2026 

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Issued: 120 PM CDT Tue Sep 8 2026
Key Messages
- Showers and a few storms will move across the area late tonight through Wednesday.
- Thursday and Friday look pleasant.
- The next opportunities for rain will arrive this weekend and continue into early next week.
Discussion
... Issued at 120 PM CDT Tue Sep 8 2026
Per a recent subjective surface analyses, a 1000 mb surface low pressure system is moving across southern Manitoba well to the north of a surface high pressure system parked along the Atlantic coast. A cold front extends southward...
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