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Izaac Walton Lake, IL Weather Forecast
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Izaac Walton Lake Weather Forecast
| TONIGHT | SUNDAY | SUNDAY NIGHT | MONDAY | MONDAY NIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY |
 |  |  | |  | | |  |  |  | |  |
| Mostly Clear | Mostly Sunny | Chance of T-Storm | Mostly Sunny | Partly Cloudy | Mostly Clear | Mostly Clear | Chance of Showers | Chance of Showers | Chance of Showers | Partly Cloudy | Partly Cloudy |
| Lo: 75°FLo: 24°C | Hi: 99°FHi: 37°C | Lo: 71°FLo: 22°C | Hi: 89°FHi: 32°C | Lo: 65°FLo: 18°C | Hi: 90°FHi: 32°C Lo: 70°FLo: 21°C | Hi: 90°FHi: 32°C Lo: 70°FLo: 21°C | Hi: 91°FHi: 33°C | Lo: 69°FLo: 21°C | Hi: 85°FHi: 29°C | Hi: 85°FHi: 29°C Lo: 65°FLo: 18°C | Hi: 85°FHi: 29°C Lo: 65°FLo: 18°C |
| POP: 30% | POP: 30% | POP: 40% | POP: 40% |
POP = Probability of Precipitation.
Weather Outlook Updated: 817 PM CDT Sat Aug 15 2026 
Izaac Walton Lake Radar Loop
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Izaac Walton Lake Weather Map
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Izaac Walton Lake Forecast Discussion
Issued: 649 PM CDT Sat Aug 15 2026
Key Messages
- An Extreme Heat Warning continues thru tomorrow with Heat Indices peaking in the triple digits up to near 115 degrees.
- Storm chances, including strong storm chances, are best with frontal passages Sunday night and Thursday. Both frontal passages bring cooler temperatures and lower humidity.
Discussion
... Issued at 1241 PM CDT Sat Aug 15 2026
When you look at an upper level chart you can see about a 600dm ridge at 500mb centered just to the southwest of the...