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Arrowhead Lake Weather Forecast
| TODAY | TONIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY | SATURDAY NIGHT |
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| Mostly Sunny | Partly Cloudy | Chance of T-Storm | Chance of T-Storm | Chance of T-Storm | Partly Cloudy | Partly Cloudy | Mostly Cloudy | Mostly Cloudy | Partly Cloudy | Chance of Showers | Chance of Showers |
| Hi: 81°FHi: 27°C | Lo: 69°FLo: 21°C | Hi: 91°FHi: 33°C | Lo: 69°FLo: 21°C | Hi: 90°FHi: 32°C | Hi: 90°FHi: 32°C Lo: 71°FLo: 22°C | Hi: 90°FHi: 32°C Lo: 71°FLo: 22°C | Hi: 89°FHi: 32°C Lo: 69°FLo: 21°C | Hi: 89°FHi: 32°C Lo: 69°FLo: 21°C | Lo: 69°FLo: 21°C | Hi: 85°FHi: 29°C | Hi: 81°FHi: 27°C Lo: 65°FLo: 18°C |
| POP: 40% | POP: 70% | POP: 70% | POP: 30% | POP: 40% |
POP = Probability of Precipitation.
Weather Outlook Updated: 437 AM CDT Mon Sep 14 2026 
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Issued: 234 AM CDT Mon Sep 14 2026
Key Messages
- Near-term conditions remain dry and pleasant today, with increasing southeasterly winds gusting 15-25 mph this afternoon.
- Active weather returns Tuesday and Wednesday as a cold front stalls across central Illinois, bringing multiple rounds of showers and thunderstorms through the end of the week and weekend.
- Severe weather is possible both Tuesday and Wednesday, with localized heavy rainfall (1-2+ inches, particularly northwest of a Havana to Bloomington line).
- A strong north-to-sout...