Belleville, IL Weather & Growing Conditions
This Afternoon
97°F
Mostly Sunny
Mostly sunny, with a high near 97. Heat index values as high as 101. Southwest wind around 6 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 97°F | Mostly Sunny | 6 mph SW | 1% |
| Tonight | 73°F | Partly Cloudy | 2 to 6 mph SW | 2% |
| Sunday | 93°F | Mostly Sunny | 6 mph W | 8% |
| Sunday Night | 67°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 to 8 mph NE | 67% |
| Monday | 81°F | Showers And Thunderstorms Likely | 5 to 9 mph NE | 67% |
| Monday Night | 61°F | Chance Showers And Thunderstorms | 5 to 9 mph NE | 44% |
| Tuesday | 73°F | Slight Chance Rain Showers then Mostly Cloudy | 7 to 12 mph N | 19% |
| Tuesday Night | 55°F | Mostly Cloudy | 5 to 12 mph N | 1% |
| Wednesday | 74°F | Mostly Sunny | 9 mph N | 0% |
| Wednesday Night | 54°F | Partly Cloudy | 2 to 8 mph N | 0% |
| Thursday | 76°F | Mostly Sunny | 3 to 7 mph N | 1% |
| Thursday Night | 58°F | Mostly Cloudy | 2 to 6 mph NE | 7% |
| Friday | 79°F | Slight Chance Rain Showers | 2 to 7 mph NE | 17% |
| Friday Night | 58°F | Slight Chance Rain Showers then Mostly Cloudy | 2 to 6 mph NE | 17% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Belleville, IL
Last spring frost
Apr 12
First fall frost
Oct 20
Growing season
189 days
Hardiness zone
7a
Explore more for Belleville, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Belleville Siu Rsch, Il (8.7 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 20, 2026.