Glen Carbon, IL Weather & Growing Conditions
Tonight
73°F
Partly Cloudy
Partly cloudy, with a low around 73. Southeast wind around 7 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 73°F | Partly Cloudy | 7 mph SE | 9% |
| Saturday | 98°F | Mostly Sunny | 5 to 8 mph SW | 6% |
| Saturday Night | 74°F | Partly Cloudy | 6 mph S | 2% |
| Sunday | 94°F | Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms | 3 to 8 mph W | 20% |
| Sunday Night | 68°F | Slight Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 9 mph N | 59% |
| Monday | 81°F | Rain Showers Likely | 7 to 12 mph NE | 69% |
| Monday Night | 61°F | Showers And Thunderstorms Likely | 8 to 13 mph N | 69% |
| Tuesday | 72°F | Chance Rain Showers then Mostly Cloudy | 13 mph N | 28% |
| Tuesday Night | 56°F | Mostly Cloudy | 6 to 13 mph N | 6% |
| Wednesday | 76°F | Mostly Sunny | 7 to 10 mph N | 3% |
| Wednesday Night | 56°F | Partly Cloudy | 3 to 9 mph N | 2% |
| Thursday | 76°F | Mostly Sunny | 3 to 9 mph N | 3% |
| Thursday Night | 59°F | Partly Cloudy | 3 to 8 mph N | 3% |
| Friday | 77°F | Mostly Sunny | 5 to 8 mph N | 6% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Glen Carbon, IL
Last spring frost
Apr 4
First fall frost
Nov 5
Growing season
214 days
Hardiness zone
7a
Explore more for Glen Carbon, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Alton - Melvin Price L&D, Il (12.3 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.