Glen Carbon, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Glen Carbon, a village in Madison County, Illinois.
Tonight
73°F
Slight Chance Showers And Thunderstorms then Mostly Clear
A slight chance of showers and thunderstorms before 10pm. Mostly clear, with a low around 73. Heat index values as high as 100. Southeast wind around 6 mph. Chance of precipitation is 20%.
7-day forecast for Glen Carbon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 73°F | Slight Chance Showers And Thunderstorms then Mostly Clear | 6 mph SE | 23% |
| Saturday | 98°F | Mostly Sunny | 5 to 8 mph SW | 6% |
| Saturday Night | 74°F | Partly Cloudy | 6 mph S | 2% |
| Sunday | 93°F | Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms | 3 to 8 mph W | 20% |
| Sunday Night | 67°F | Slight Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 9 mph N | 60% |
| Monday | 80°F | Rain Showers Likely | 7 to 13 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 | 55°F | Mostly Cloudy | 6 to 13 mph N | 6% |
| Wednesday | 75°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 | 58°F | Partly Cloudy | 3 to 9 mph N | 3% |
| Friday | 77°F | Mostly Sunny | 5 to 8 mph N | 6% |
Forecast source: National Weather Service (api.weather.gov) for Glen Carbon (38.758, -89.983). Updated through the day.
Growing snapshot for Glen Carbon
Last spring frost
Apr 4
First fall frost
Nov 5
Growing season
214 days
Hardiness zone
7a
More local growing data for Glen Carbon: nearby ZIP 62034 weather · frost dates · planting calendar · Illinois frost dates
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Climate data from the nearest NOAA station, Alton - Melvin Price L&D, Il (12.3 mi from Glen Carbon). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.