When to plant in Napa, CA
USDA Zone 9bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Napa, California — all computed from Napa's nearest NOAA weather station.
A generous ~295-day season lets Napa gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. In zone 9b, frost is a minor factor for Napa — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
NAPA STATE HOSPITAL · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Napa’s own odds, recorded at NAPA STATE HOSPITAL.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 19 | Mar 27 | Feb 26 | Oct 31 | Nov 17 | Dec 4 |
| 32°F | Mar 13 | Feb 12 | Jan 3 | Nov 15 | Dec 4 | Jan 4 |
| 28°F | Feb 13 | Jan 11 | Dec 16 | Dec 1 | Dec 19 | Jan 23 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Napa, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 14 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Napa planting FAQ
When is the last spring frost in Napa, CA?
On average, the last spring frost in Napa is around February 12 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Napa, CA?
In Napa, the first 32°F freeze of fall lands around December 4 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Napa in?
Napa is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Napa?
Napa has about 295 frost-free days — a long growing season — between the average last spring frost (February 12) and first fall frost (December 4).
When should I plant tomatoes in Napa?
For Napa, sow tomatoes indoors about December 18–January 1 and move the seedlings out around February 19, after the last spring frost.
Never miss a window in Napa
An email when it’s time to start seeds, transplant, and sow — timed to Napa’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- American Canyon · 14 km
- Sonoma · 14 km
- Vallejo · 21 km
- Fairfield · 24 km
- Suisun City · 26 km
- Benicia · 28 km
- Petaluma · 29 km
- Vacaville · 30 km
Frost dates recorded at NAPA STATE HOSPITAL, 4 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Napa, CA — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00046074. Retrieved from https://blissgarden.com/california/napa.