Mercer County, Illinois
Local growing conditions for Mercer County: the USDA hardiness zones found here, frost dates, and live weather for communities across the county. Based on 13 ZIP codes in our data.
Hardiness zones in Mercer County
Mercer County spans these USDA plant hardiness zones (by number of ZIP codes):
Local weather & frost dates
Open any community in Mercer County for its live forecast, frost dates, and planting calendar:
Aledo 61231
Joy 61260
Matherville 61263
Eliza 61272
Preemption 61276
Hamlet 61279
Cable 61281
Alexis 61412
Keithsburg 61442
Windsor 61465
North Henderson 61466
Seaton 61476
Viola 61486
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.