Modesto, CA Frost Dates
Average frost dates, USDA hardiness zone, and growing season length for Modesto, California.
Gardening in Modesto
Central Valley practical — Modesto doesn't have San Francisco's foodie pretension, but its gardens produce food with a generosity that coastal cities can't match.
Zone 9a in the heart of California's Central Valley. Rich alluvial soil, hot dry summers, and a long growing season. Commercial agriculture surrounds the city, and home gardens inherit the same conditions.
The Modesto Certified Farmers Market connects the city to the valley's agricultural abundance. George Lucas grew up here, and while Modesto's most famous export is American Graffiti, its most productive one is food.
What This Means for Modesto Gardeners
The average last spring frost in Modesto is around February 20, and the average first fall frost arrives around November 20. That gives you approximately 273 frost-free days to work with.
273 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 20, 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 Modesto 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 Modesto
Modesto's 273-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 Modesto.
More About Zone 9A
Modesto 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 Modesto 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 Modesto (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 20). 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.