Flat Rock, IL Weather & Growing Conditions
Tonight
60°F
Showers And Thunderstorms
Showers and thunderstorms after 8pm. Mostly cloudy, with a low around 60. South wind 12 to 18 mph, with gusts as high as 28 mph. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 60°F | Showers And Thunderstorms | 12 to 18 mph S | 93% |
| Wednesday | 67°F | Chance Light Rain then Partly Sunny | 8 to 14 mph SW | 32% |
| Wednesday Night | 46°F | Mostly Cloudy | 6 mph SW | 0% |
| Thursday | 66°F | Sunny | 5 to 13 mph SW | 0% |
| Thursday Night | 45°F | Partly Cloudy | 5 mph WNW | 3% |
| Friday | 59°F | Partly Sunny | 3 to 10 mph NNW | 4% |
| Friday Night | 39°F | Partly Cloudy | 3 to 7 mph NNW | 4% |
| Saturday | 56°F | Mostly Sunny | 6 mph NNW | 1% |
| Saturday Night | 35°F | Partly Cloudy | 3 mph WNW | 2% |
| Sunday | 61°F | Sunny | 2 to 8 mph W | 7% |
| Sunday Night | 35°F | Mostly Clear | 2 to 6 mph WNW | 7% |
| Monday | 63°F | Sunny | 2 to 9 mph W | 3% |
| Monday Night | 39°F | Mostly Clear | 6 mph SW | 1% |
| Tuesday | 67°F | Sunny | 7 mph WSW | 1% |
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 Nov 4, 2026.