Weather World
Flat Rock, IL Weather Forecast
Quick Weather Clicks
Settings
Sun & Moon
Flat Rock Weather Forecast
| TONIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY | SATURDAY NIGHT | SUNDAY | MONDAY | TUESDAY | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY |
 |  | | | | | | | |  |  |
| Mostly Clear | Sunny | Mostly Clear | Sunny | Mostly Clear | Mostly Clear | Mostly Clear | Mostly Clear | Mostly Clear | Partly Cloudy | Partly Cloudy |
| Lo: 75°FLo: 24°C | Hi: 99°FHi: 37°C | Lo: 75°FLo: 24°C | Hi: 99°FHi: 37°C | Lo: 69°FLo: 21°C | Hi: 90°FHi: 32°C Lo: 65°FLo: 18°C | Hi: 90°FHi: 32°C Lo: 65°FLo: 18°C | Hi: 99°FHi: 37°C Lo: 71°FLo: 22°C | Hi: 99°FHi: 37°C Lo: 71°FLo: 22°C | Hi: 95°FHi: 35°C Lo: 71°FLo: 22°C | Hi: 95°FHi: 35°C Lo: 71°FLo: 22°C |
POP = Probability of Precipitation.
Weather Outlook Updated: 437 PM CDT Thu Sep 03 2026 
Flat Rock Radar Loop
Use the map search tool if you want to place a location marker on the radar map...
Flat Rock Weather Map
Flat Rock Quick Facts
Flat Rock Forecast Discussion
Meteorlogic Glosserator
Instant definitions for any meteorological term.
Instant definitions for any meteorological term.
Issued: 147 PM CDT Thu Sep 3 2026
Key Messages
- An Extreme Heat Warning remains in effect areawide through Friday and for parts of the area Saturday with dangerous heat index values between 100 and 109 degrees.
- There is a very low chance (10-15%) for an isolated severe thunderstorm late this afternoon and evening and again Friday afternoon and evening. The primary threat will be damaging wind gusts. A marginal severe risk lingers over portions of east central Illinois Saturday.
Discussion
... Issued at 142 PM CDT Thu Sep 3 2026
Exces...