Harrisburg, IL Weather & Growing Conditions
Overnight
57°F
Mostly Cloudy
Mostly cloudy. Low around 57, with temperatures rising to around 59 overnight. South southwest wind around 6 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 57°F | Mostly Cloudy | 6 mph SSW | 13% |
| Wednesday | 65°F | Partly Sunny | 5 to 10 mph WSW | 10% |
| Wednesday Night | 43°F | Mostly Clear | 3 mph WSW | 0% |
| Thursday | 68°F | Sunny | 2 to 8 mph WSW | 0% |
| Thursday Night | 44°F | Partly Cloudy | 2 mph W | 0% |
| Friday | 61°F | Partly Sunny | 1 to 10 mph NNW | 0% |
| Friday Night | 36°F | Partly Cloudy | 1 to 8 mph N | 0% |
| Saturday | 57°F | Mostly Sunny | 1 to 6 mph NNW | 0% |
| Saturday Night | 32°F | Partly Cloudy | 1 mph NNW | 0% |
| Sunday | 61°F | Sunny | 0 to 6 mph NNW | 0% |
| Sunday Night | 33°F | Clear | 2 mph NW | 1% |
| Monday | 64°F | Sunny | 0 to 5 mph WSW | 0% |
| Monday Night | 37°F | Clear | 2 mph SW | 1% |
| Tuesday | 69°F | Sunny | 0 to 5 mph WSW | 1% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Harrisburg, IL
Last spring frost
Apr 7
First fall frost
Oct 26
Growing season
202 days
Hardiness zone
7a
Explore more for Harrisburg, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Harrisburg, Il (2.8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.