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Castleton, IL Weather Forecast
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Castleton Weather Forecast
| TODAY | TONIGHT | SUNDAY | SUNDAY NIGHT | LABOR DAY | MONDAY NIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | FRIDAY |
 |  | |  | | |  | | |  | | |
| Sunny | Mostly Clear | Mostly Sunny | Clearing | Sunny | Partly Cloudy | Partly Cloudy | Partly Cloudy | Partly Cloudy | Chance of Showers | Partly Cloudy | Partly Cloudy |
| Hi: 90°FHi: 32°C | Lo: 65°FLo: 18°C | Hi: 81°FHi: 27°C | Lo: 61°FLo: 16°C | Hi: 81°FHi: 27°C | Hi: 90°FHi: 32°C Lo: 61°FLo: 16°C | Hi: 90°FHi: 32°C Lo: 61°FLo: 16°C | Hi: 89°FHi: 32°C Lo: 71°FLo: 22°C | Hi: 89°FHi: 32°C Lo: 71°FLo: 22°C | Lo: 61°FLo: 16°C | Hi: 85°FHi: 29°C Lo: 61°FLo: 16°C | Hi: 85°FHi: 29°C Lo: 61°FLo: 16°C |
| POP: 30% |
POP = Probability of Precipitation.
Weather Outlook Updated: 437 AM CDT Sat Sep 05 2026 
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Issued: 554 AM CDT Sat Sep 5 2026
Key Messages
- Dangerous Heat Today: Heat index values will reach to around 105 degrees again today. The Extreme Heat Warning covers all of central Illinois.
- Brief Weekend Relief: A cold front pushing south will bring slightly less hot and humid conditions to northern areas Sunday and Monday, dropping highs into the mid-to-upper 80s. Southern areas will remain warmer, around 90.
- Heat Returns Next Week: The brief break in oppressive heat will be short-lived. Widespread 90-degree temperatures are for...