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Merna, IL Weather Forecast
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Merna Weather Forecast
| TONIGHT | SATURDAY | SATURDAY NIGHT | SUNDAY | SUNDAY NIGHT | MONDAY | MONDAY NIGHT | TUESDAY | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | FRIDAY |
 |  |  |  | | |  |  | | |  | |
| Partly Cloudy | Chance of T-Storm | Chance of T-Storm | Chance of Showers | Chance of T-Storm | Chance of T-Storm | Chance of Showers | Mostly Cloudy | Mostly Cloudy | Partly Cloudy | Partly Cloudy | Partly Cloudy |
| Lo: 69°FLo: 21°C | Hi: 85°FHi: 29°C | Lo: 69°FLo: 21°C | Hi: 79°FHi: 26°C | Lo: 59°FLo: 15°C | Hi: 69°FHi: 21°C | Lo: 51°FLo: 11°C | Hi: 69°FHi: 21°C Lo: 51°FLo: 11°C | Hi: 69°FHi: 21°C Lo: 51°FLo: 11°C | Hi: 71°FHi: 22°C Lo: 51°FLo: 11°C | Hi: 71°FHi: 22°C Lo: 51°FLo: 11°C | Hi: 71°FHi: 22°C Lo: 51°FLo: 11°C |
| POP: 40% | POP: 50% | POP: 70% | POP: 70% | POP: 70% | POP: 50% |
POP = Probability of Precipitation.
Weather Outlook Updated: 742 PM CDT Fri Sep 18 2026 
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Instant definitions for any meteorological term.
Issued: 548 PM CDT Fri Sep 18 2026
Key Messages
- Unseasonable Heat & Temperature Contrast: Areas south of the front will see heat indices near 100 F through Saturday. This is primarily near and south of Interstate 72.
- Thunderstorms & Microburst Risk: Scattered showers and storms are forecast through Sunday. On Saturday, stronger storms could produce localized damaging wind gusts up to 60 mph and quarter-sized hail.
- Significantly Cooler Next Week: High confidence that the hot air will be pushed south by Monday. Expect comfortable, d...