Jefferson County, Wisconsin
Local growing conditions for Jefferson County: the USDA hardiness zones found here, frost dates, and live weather for communities across the county. Based on 10 ZIP codes in our data.
Hardiness zones in Jefferson County
Jefferson County spans these USDA plant hardiness zones (by number of ZIP codes):
Local weather & frost dates
Open any community in Jefferson County for its live forecast, frost dates, and planting calendar:
Lake Koshkonong 53538
Waterloo 53594
Ixonia 53036
Johnson Creek 53038
Watertown 53094
Rome 53137
Palmyra 53156
Sullivan 53178
Jefferson 53549
Lake Mills 53551
More for Wisconsin
- Agriculture in Wisconsin
- Frost dates across Wisconsin
- 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.