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Monticello, IL Weather Forecast
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Monticello Weather Forecast
| REST OF TONIGHT | SUNDAY | SUNDAY NIGHT | MONDAY | MONDAY NIGHT | TUESDAY | WEDNESDAY | THURSDAY | FRIDAY | SATURDAY |
 |  | | | | | | | | |
| Clear | Sunny | Clear | Sunny | Mostly Clear | Mostly Clear | Mostly Clear | Mostly Clear | Mostly Clear | Mostly Clear |
| Lo: 31°FLo: -1°C | Hi: 69°FHi: 21°C | Lo: 35°FLo: 2°C | Hi: 71°FHi: 22°C | Lo: 39°FLo: 4°C | Hi: 75°FHi: 24°C Lo: 45°FLo: 7°C | Hi: 75°FHi: 24°C Lo: 45°FLo: 7°C | Hi: 75°FHi: 24°C Lo: 45°FLo: 7°C | Hi: 75°FHi: 24°C Lo: 45°FLo: 7°C | Hi: 75°FHi: 24°C Lo: 45°FLo: 7°C |
POP = Probability of Precipitation.
Weather Outlook Updated: 908 PM CDT Sat Oct 17 2026 
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Issued: 607 PM CDT Sat Oct 17 2026
Key Messages
- Frost will be likely across areas generally east of I-55 tonight. Sensitive outdoor plants need to be protected this weekend in order to avoid damage. A Frost Advisory is in effect tonight near and east of a Bloomington...to Decatur...to Taylorville line.
- Temperatures will begin a warming trend. Highs tomorrow will be in the mid 60s, but by midweek temperatures will be back well above normal with highs in the upper 70s, nearing 80.
Discussion
... Issued at 220 PM CDT Sat Oct 17 2026
Hig...