O'Brien County, Iowa
Local growing conditions for O'Brien County: the USDA hardiness zones found here, frost dates, and live weather for communities across the county. Based on 8 ZIP codes in our data.
Hardiness zones in O'Brien County
O'Brien County spans these USDA plant hardiness zones (by number of ZIP codes):
Local weather & frost dates
Open any community in O'Brien County for its live forecast, frost dates, and planting calendar:
Calumet 51009
Granville 51022
Paullina 51046
Sutherland 51058
Archer 51231
Primghar 51245
Sanborn 51248
Hartley 51346
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.