Williamson County, Illinois
Local growing conditions for Williamson County: the USDA hardiness zones found here, frost dates, and live weather for communities across the county. Based on 12 ZIP codes in our data.
Hardiness zones in Williamson County
Williamson County spans these USDA plant hardiness zones (by number of ZIP codes):
Local weather & frost dates
Open any community in Williamson County for its live forecast, frost dates, and planting calendar:
Freeman Spur 62841
Carbondale 62902
Cambria 62915
Carterville 62918
Carterville 62921
Creal Springs 62922
Energy 62933
Herrin 62948
Hurst 62949
Johnston City 62951
Marion 62959
Pittsburg 62974
More for Illinois
- Agriculture in Illinois
- Frost dates across Illinois
- USDA hardiness zones explained
- Planting calendar by ZIP code
County growing conditions are compiled from our ZIP-code database, USDA hardiness-zone data, and NOAA climate normals. Conditions vary within a county by elevation and local microclimate. Page updated Aug 4, 2026.