Glen Carbon, IL Weather & Growing Conditions
Overnight
55°F
Slight Chance Light Rain
A slight chance of rain before 3am, then a slight chance of drizzle. Mostly cloudy, with a low around 55. Southwest wind around 10 mph. Chance of precipitation is 20%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 55°F | Slight Chance Light Rain | 10 mph SW | 17% |
| Wednesday | 63°F | Slight Chance Drizzle then Mostly Cloudy | 8 to 14 mph W | 12% |
| Wednesday Night | 46°F | Partly Cloudy | 7 mph W | 0% |
| Thursday | 64°F | Sunny | 6 to 12 mph W | 0% |
| Thursday Night | 48°F | Mostly Cloudy | 6 mph NW | 3% |
| Friday | 57°F | Partly Sunny | 7 to 12 mph N | 1% |
| Friday Night | 37°F | Partly Cloudy | 2 to 8 mph N | 0% |
| Saturday | 56°F | Mostly Sunny | 5 mph N | 0% |
| Saturday Night | 36°F | Partly Cloudy | 2 mph NW | 0% |
| Sunday | 60°F | Sunny | 2 to 7 mph NW | 1% |
| Sunday Night | 37°F | Clear | 2 mph W | 0% |
| Monday | 66°F | Sunny | 1 to 6 mph SW | 0% |
| Monday Night | 42°F | Clear | 2 mph SW | 0% |
| Tuesday | 68°F | Sunny | 5 mph W | 1% |
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 Nov 4, 2026.