St. Mary's County, Maryland
Local growing conditions for St. Mary's County: the USDA hardiness zones found here, frost dates, and live weather for communities across the county. Based on 26 ZIP codes in our data.
Hardiness zones in St. Mary's County
St. Mary's County spans these USDA plant hardiness zones (by number of ZIP codes):
Local weather & frost dates
Open any community in St. Mary's County for its live forecast, frost dates, and planting calendar:
Lexington Park 20670
St. George Island 20684
Rock Point 20606
Rock Point 20609
Rock Point 20618
California 20619
Callaway 20620
Rock Point 20621
Leonardtown 20624
Cobb Island 20626
Lexington Park 20628
Piney Point 20630
Callaway 20634
Wildewood 20636
Leonardtown 20650
Lexington Park 20653
Leonardtown 20656
Mechanicsville 20659
Mechanicsville 20660
Lexington Park 20667
Tall Timbers 20674
St. George Island 20680
Lexington Park 20686
St. George Island 20687
More for Maryland
- Agriculture in Maryland
- Frost dates across Maryland
- 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.