Harrisburg, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Harrisburg, a city in Saline County, Illinois.
Today
87°F
Patchy Fog then Sunny
Patchy fog before 8am. Sunny, with a high near 87. East northeast wind 0 to 3 mph.
7-day forecast for Harrisburg
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 87°F | Patchy Fog then Sunny | 0 to 3 mph ENE | 0% |
| Tonight | 63°F | Mostly Clear | 2 mph ENE | 0% |
| Wednesday | 90°F | Sunny | 2 mph S | 0% |
| Wednesday Night | 68°F | Mostly Clear | 2 mph SSE | 2% |
| Thursday | 90°F | Slight Chance Rain Showers | 1 to 6 mph SSW | 21% |
| Thursday Night | 71°F | Chance Showers And Thunderstorms | 0 to 5 mph S | 52% |
| Friday | 90°F | Chance Showers And Thunderstorms | 1 to 5 mph SSW | 52% |
| Friday Night | 70°F | Chance Showers And Thunderstorms | 2 mph SSW | 32% |
| Saturday | 90°F | Chance Showers And Thunderstorms | 1 to 5 mph SSW | 32% |
| Saturday Night | 70°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 3 mph SSW | 20% |
| Sunday | 92°F | Sunny | 2 to 8 mph SSW | 8% |
| Sunday Night | 72°F | Mostly Clear | 2 to 7 mph SSW | 5% |
| Monday | 93°F | Sunny | 3 to 9 mph SSW | 5% |
| Monday Night | 74°F | Mostly Clear | 3 to 8 mph SSW | 7% |
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 Aug 4, 2026.