Grant County, Oregon
Local growing conditions for Grant County: the USDA hardiness zones found here, frost dates, and live weather for communities across the county. Based on 11 ZIP codes in our data.
Hardiness zones in Grant County
Grant County spans these USDA plant hardiness zones (by number of ZIP codes):
Local weather & frost dates
Open any community in Grant County for its live forecast, frost dates, and planting calendar:
Seneca 97873
Greenhorn 97817
Seneca 97820
Dayville 97825
John Day 97845
Monument 97848
Long Creek 97856
Monument 97864
Mount Vernon 97865
Prairie City 97869
Granite 97877
More for Oregon
- Agriculture in Oregon
- Frost dates across Oregon
- 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.