Napa, CA Frost Dates
Average frost dates, USDA hardiness zone, and growing season length for Napa, California.
Gardening in Napa
Wine Country's world-famous growing conditions extend to home gardens that produce food of extraordinary quality — the same volcanic soil and Mediterranean climate that grows Cabernet grows everything else.
Zone 9a with 263 frost-free days. The Napa Valley's volcanic soil is legendarily fertile. Morning fog gives way to warm afternoons. The valley's heat accumulation grows wine grapes and warm-season vegetables with equal authority.
The Napa Valley's food-and-wine culture needs no introduction. Home gardeners benefit from the same conditions that made this the most famous agricultural valley in America.
What This Means for Napa Gardeners
The average last spring frost in Napa is around February 28, and the average first fall frost arrives around November 18. That gives you approximately 263 frost-free days to work with.
263 days is a long, productive season that supports two full rounds of warm-season crops plus continuous cool-season production through your mild winter. Most frost-sensitive crops can be transplanted by February 28, giving them months to produce before fall. Your winter garden is the real advantage — growing fresh vegetables in December and January while northern gardeners browse seed catalogs.
These dates are based on NOAA 30-year Climate Normal data for the Napa area. Your actual frost dates could shift 2-3 weeks in either direction in any given year. Learn more about our data sources.
What to Grow in Napa
Napa's 263-day growing season is generous — long enough for two full growing windows (spring and fall) with warm-season crops between them. You can grow the full range of vegetables, herbs, and flowers with proper timing. Focus on heat-tolerant varieties for midsummer and cool-season crops for extended fall harvests. Recommended starting points: tomatoes, peppers, beans, cucumbers, squash, garlic, kale, and sunflowers.
See the full California planting guide for all 40 plants: California Planting Calendar. Or enter your zip code for exact planting dates personalized to Napa.
More About Zone 9A
Napa is in USDA Hardiness Zone 9A, which means average annual extreme minimum temperatures between 20°F to 25°F. View the full Zone 9A planting guide.
See the complete planting calendar for California: California Planting Calendar.
Other Cities in California
Frequently Asked Questions
These dates are based on NOAA's 30-year Climate Normal data for the Napa area. They represent historical averages, not predictions. In any given year, the actual last frost could be 2-3 weeks earlier or later. Microclimates within Napa (urban heat islands, hilltops, low-lying valleys) can also shift your local frost dates by a week or more.
Cool-season crops go in 3-4 weeks before your last frost (February 28). Warm-season crops wait until 2 weeks after. You have time for a fall round too — plant cool-season crops again in late summer for harvest into autumn. Enter your zip code for exact dates.