Belvidere, IL Weather & Growing Conditions
Overnight
57°F
Rain Showers
Rain showers. Cloudy. Low around 57, with temperatures rising to around 60 overnight. South wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 57°F | Rain Showers | 15 mph S | 83% |
| Wednesday | 62°F | Slight Chance Rain Showers | 15 mph SSW | 22% |
| Wednesday Night | 45°F | Mostly Cloudy then Slight Chance Rain Showers | 15 mph SW | 21% |
| Thursday | 55°F | Chance Rain Showers | 10 to 15 mph W | 51% |
| Thursday Night | 38°F | Chance Rain Showers then Mostly Cloudy | 10 mph NW | 32% |
| Friday | 49°F | Partly Sunny | 10 to 15 mph N | 6% |
| Friday Night | 30°F | Partly Cloudy | 0 to 10 mph NNW | 0% |
| Saturday | 51°F | Sunny | 0 to 5 mph NW | 0% |
| Saturday Night | 31°F | Mostly Clear | 0 to 5 mph W | 0% |
| Sunday | 55°F | Sunny | 5 to 10 mph W | 6% |
| Sunday Night | 33°F | Mostly Clear | 0 to 5 mph W | 0% |
| Monday | 61°F | Sunny | 0 to 10 mph SW | 0% |
| Monday Night | 38°F | Partly Cloudy | 5 mph WSW | 0% |
| Tuesday | 61°F | Sunny | 0 to 5 mph WNW | 0% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Belvidere, IL
Last spring frost
Apr 28
First fall frost
Oct 12
Growing season
166 days
Hardiness zone
5b
Explore more for Belvidere, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Marengo, Il (11.9 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.