St. Charles County, Missouri
Local growing conditions for St. Charles County: the USDA hardiness zones found here, frost dates, and live weather for communities across the county. Based on 14 ZIP codes in our data.
Hardiness zones in St. Charles County
St. Charles County spans these USDA plant hardiness zones (by number of ZIP codes):
Local weather & frost dates
Open any community in St. Charles County for its live forecast, frost dates, and planting calendar:
Weldon Spring Heights 63304
St. Charles 63301
St. Peters 63303
Augusta 63332
Defiance 63341
Foristell 63348
New Melle 63365
St. Paul 63366
Lake St. Louis 63367
O'Fallon 63368
Portage Des Sioux 63373
St. Peters 63376
Wentzville 63385
West Alton 63386
More for Missouri
- Agriculture in Missouri
- Frost dates across Missouri
- 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.