Harrisburg, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Harrisburg, a city in Saline County, Illinois.
Tonight
57°F
Showers And Thunderstorms
Showers and thunderstorms before 5am. Mostly cloudy. Low around 57, with temperatures rising to around 59 overnight. South southwest wind 6 to 13 mph, with gusts as high as 23 mph. Chance of precipitation is 100%.
7-day forecast for Harrisburg
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 57°F | Showers And Thunderstorms | 6 to 13 mph SSW | 98% |
| Wednesday | 69°F | Partly Sunny | 5 to 10 mph WSW | 10% |
| Wednesday Night | 43°F | Partly Cloudy | 3 mph SW | 0% |
| Thursday | 69°F | Sunny | 1 to 7 mph SW | 0% |
| Thursday Night | 44°F | Partly Cloudy | 2 mph W | 5% |
| Friday | 62°F | Partly Sunny | 2 to 9 mph NNW | 5% |
| Friday Night | 38°F | Mostly Cloudy | 1 to 6 mph NNW | 1% |
| Saturday | 58°F | Mostly Sunny | 1 to 5 mph NNW | 0% |
| Saturday Night | 34°F | Partly Cloudy | 1 mph NNW | 1% |
| Sunday | 62°F | Sunny | 0 to 7 mph WNW | 5% |
| Sunday Night | 33°F | Mostly Clear | 3 mph NW | 6% |
| Monday | 65°F | Sunny | 1 to 8 mph WNW | 2% |
| Monday Night | 37°F | Mostly Clear | 1 to 5 mph SW | 0% |
| Tuesday | 69°F | Sunny | 1 to 6 mph WSW | 1% |
Forecast source: National Weather Service (api.weather.gov) for Harrisburg (37.738, -88.546). Updated through the day.
Growing snapshot for Harrisburg
Last spring frost
Apr 7
First fall frost
Oct 26
Growing season
202 days
Hardiness zone
7a
More local growing data for Harrisburg: nearby ZIP 62965 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Harrisburg, Il (1.9 mi from Harrisburg). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.