Weather WorldFlat Lake, IL Weather Forecast
Quick Weather Clicks
Settings
Sun & Moon
Flat Lake Weather Forecast
| TONIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY | SATURDAY NIGHT | SUNDAY | SUNDAY NIGHT | COLUMBUS DAY |
 |  | | | | | | |  |  |  |  |
| Clear | Sunny | Mostly Clear | Sunny | Mostly Clear | Sunny | Clear | Sunny | Chance of Showers | Chance of Showers | Partly Cloudy | Partly Cloudy |
| Lo: 51°FLo: 11°C | Hi: 89°FHi: 32°C | Lo: 55°FLo: 13°C | Hi: 80°FHi: 27°C | Lo: 51°FLo: 11°C | Hi: 85°FHi: 29°C | Lo: 59°FLo: 15°C | Hi: 89°FHi: 32°C | Lo: 59°FLo: 15°C | Hi: 81°FHi: 27°C | Hi: 85°FHi: 29°C Lo: 59°FLo: 15°C | Hi: 85°FHi: 29°C Lo: 59°FLo: 15°C |
| POP: 20% | POP: 30% |
POP = Probability of Precipitation.
Weather Outlook Updated: 732 PM CDT Tue Oct 06 2026 
Flat Lake Radar Loop
Use the map search tool if you want to place a location marker on the radar map...
Flat Lake Weather Map
Flat Lake Quick Facts
Flat Lake Forecast Discussion
Meteorlogic Glosserator
Instant definitions for any meteorological term.
Instant definitions for any meteorological term.
Issued: 627 PM CDT Tue Oct 6 2026
Key Messages
- No precipitation and above average temperatures are forecast through the week.
Aviation
/00Z TAFS THROUGH 06Z THURSDAY/... Issued at 623 PM CDT Tue Oct 6 2026
Light winds and a clear sky are expected overnight, with winds turning southwesterly and then westerly during the morning on Wednesday. There remains some concern about fog developing in the river valleys overnight, most likely affecting SUS. However, confidence in this occurring is less than prior forecasts. Although it did occur...