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Merdian Lake Weather Forecast
| REST OF TODAY | TONIGHT | MONDAY | MONDAY NIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | THURSDAY | FRIDAY | SATURDAY |
 |  |  | | |  | |  | |  |
| Chance of T-Storm | Partly Cloudy | Mostly Sunny | Partly Cloudy | Mostly Sunny | Mostly Clear | Mostly Clear | Partly Cloudy | Partly Cloudy | Chance of Showers |
| Hi: 85°FHi: 29°C | Lo: 71°FLo: 22°C | Hi: 91°FHi: 33°C | Lo: 75°FLo: 24°C | Hi: 91°FHi: 33°C | Hi: 95°FHi: 35°C Lo: 75°FLo: 24°C | Hi: 95°FHi: 35°C Lo: 75°FLo: 24°C | Hi: 91°FHi: 33°C Lo: 71°FLo: 22°C | Hi: 91°FHi: 33°C Lo: 71°FLo: 22°C | Hi: 89°FHi: 32°C |
| POP: 40% | POP: 40% |
POP = Probability of Precipitation.
Weather Outlook Updated: 927 AM CDT Sun Aug 30 2026 
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Issued: 627 AM CDT Sun Aug 30 2026
Key Messages
- A late season heat wave is forecast to impact central and southeast IL much of this week. Afternoon heat indices are projected to reach upper 90s to around 100 Monday, 100-105F Tuesday through Friday, and peaking during mid week around Wed.
- Precipitation chances are low for the next several days, as an active storm track is forecast just to our north through mid week. Isolated showers and thunderstorms are possible over the IL river valley today, especially this morning. There is a 2...