Glen Carbon, IL Weather & Growing Conditions
Overnight
67°F
Clear
Clear, with a low around 67. Southeast wind around 3 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 67°F | Clear | 3 mph SE | 0% |
| Tuesday | 88°F | Sunny | 3 mph SE | 0% |
| Tuesday Night | 68°F | Mostly Clear | 5 mph SE | 0% |
| Wednesday | 90°F | Sunny | 2 to 7 mph S | 10% |
| Wednesday Night | 72°F | Slight Chance Showers And Thunderstorms | 7 mph S | 69% |
| Thursday | 87°F | Showers And Thunderstorms Likely | 7 mph S | 72% |
| Thursday Night | 70°F | Chance Showers And Thunderstorms | 5 mph SE | 40% |
| Friday | 87°F | Chance Showers And Thunderstorms | 5 mph SW | 40% |
| Friday Night | 71°F | Chance Showers And Thunderstorms | 3 mph S | 34% |
| Saturday | 89°F | Chance Showers And Thunderstorms then Mostly Sunny | 2 to 6 mph S | 34% |
| Saturday Night | 73°F | Mostly Clear | 7 mph S | 8% |
| Sunday | 92°F | Sunny | 6 to 9 mph S | 7% |
| Sunday Night | 74°F | Mostly Clear | 8 mph S | 5% |
| Monday | 93°F | Sunny | 6 to 9 mph S | 5% |
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 Aug 4, 2026.