Flat Rock, IL Weather & Growing Conditions
Today
85°F
Sunny
Sunny, with a high near 85. East northeast wind around 5 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 85°F | Sunny | 5 mph ENE | 0% |
| Tonight | 64°F | Mostly Clear | 3 mph E | 0% |
| Wednesday | 88°F | Sunny | 0 to 3 mph S | 0% |
| Wednesday Night | 68°F | Mostly Clear | 3 mph S | 7% |
| Thursday | 86°F | Chance Rain Showers then Chance Showers And Thunderstorms | 3 to 7 mph SSW | 33% |
| Thursday Night | 69°F | Chance Showers And Thunderstorms | 2 to 6 mph S | 53% |
| Friday | 85°F | Chance Showers And Thunderstorms | 2 to 7 mph SSW | 35% |
| Friday Night | 69°F | Chance Showers And Thunderstorms | 5 mph SSW | 35% |
| Saturday | 86°F | Chance Showers And Thunderstorms then Slight Chance Showers And Thunderstorms | 2 to 6 mph SSW | 25% |
| Saturday Night | 70°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 5 mph S | 21% |
| Sunday | 89°F | Sunny | 5 to 10 mph SSW | 12% |
| Sunday Night | 72°F | Mostly Clear | 8 mph SSW | 12% |
| Monday | 90°F | Sunny | 6 to 10 mph SSW | 12% |
| Monday Night | 73°F | Slight Chance Showers And Thunderstorms | 8 mph SSW | 23% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Flat Rock, IL
Last spring frost
Apr 8
First fall frost
Oct 26
Growing season
200 days
Hardiness zone
6b
Explore more for Flat Rock, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Lawrenceville Intl Ap, Il (7.9 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.