Johnson County, Iowa
Local growing conditions for Johnson 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 Johnson County
Johnson County spans these USDA plant hardiness zones (by number of ZIP codes):
Local weather & frost dates
Open any community in Johnson County for its live forecast, frost dates, and planting calendar:
Hills 52235
Iowa City 52240
Coralville 52241
Iowa City 52242
Iowa City 52245
Iowa City 52246
Kalona 52247
North Liberty 52317
Oxford 52322
Solon 52333
Swisher 52338
Tiffin 52340
Lone Tree 52755
More for Iowa
- Agriculture in Iowa
- Frost dates across Iowa
- 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.