Contra Costa County, California
Local growing conditions for Contra Costa County: the USDA hardiness zones found here, frost dates, and live weather for communities across the county. Based on 43 ZIP codes in our data.
Hardiness zones in Contra Costa County
Contra Costa County spans these USDA plant hardiness zones (by number of ZIP codes):
Local weather & frost dates
Open any community in Contra Costa County for its live forecast, frost dates, and planting calendar:
Byron 94505
Blackhawk 94506
Alamo 94507
Antioch 94509
Bethel Island 94511
Brentwood 94513
Byron 94514
Moraga 94516
Clayton 94517
Concord 94518
Concord 94519
Concord 94520
Concord 94521
Pleasant Hill 94523
Crockett 94525
Danville 94526
Diablo 94528
El Cerrito 94530
Antioch 94531
Hercules 94547
Knightsen 94548
Lafayette 94549
Alhambra Valley 94553
Moraga 94556
More for California
- Agriculture in California
- Frost dates across California
- 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.