Frost dates · USDA zone 9b
Frost dates for Napa, CA
Napa, CA sees its last 32 °F night of spring around February 12 and its first of fall around December 4 — a 299-day freeze-free season in a typical year.
Pick a sauce; the Plan Builder runs this station's dates and hands back the calendar, plant count and gear list.
Freeze odds, by date
| Odds | Last spring freeze after | First fall freeze before |
|---|---|---|
| 9 years in 10 | Jan 3 | Jan 4 (next year) |
| Median — 1 year in 2 | Feb 12 | Dec 4 |
| 1 year in 10 | Mar 13 | Nov 15 |
The top row is the risky edge: in 9 years of 10 a spring freeze still comes after it, so tender transplants set out then need cover. The bottom row is the cautious date — only 1 year in 10 freezes after it — and the one to plan uncovered tender transplants against. Freeze-free season: 299 days median, at least 257 in 9 years of 10, at least 338 days in 1 year of 10. NOAA ranks season length year by year, so it is not the gap between two rows above. A hard freeze (28 °F) has a median last date of Jan 11 and first of Dec 19.
Napa planting calendar, 2027
Every row runs from the median last frost (Feb 12) and median first frost (Dec 4) above, using each cultivar's days to maturity. Same engine as the Plan Builder.
| Crop | Start indoors | Transplant / plant | First harvest | Days |
|---|---|---|---|---|
| Hardneck GarlicSiberian (porcelain hardneck) | — | Oct 15prior fall | Jun 12 | 240 from sow |
| Spanish OnionYellow Sweet Spanish (long-day) | Nov 20 | Jan 15 | May 5 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Feb 12 | Mar 14 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Jan 29 | Jan 29 | Mar 15 | 45 from sow |
| Genovese BasilGenovese | Jan 15 | Feb 26 | Apr 27 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Dec 18 | Feb 19 | May 5 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Dec 4 | Feb 26 | Jun 1 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Dec 18 | Feb 19 | May 5 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Dec 18 | Feb 19 | May 10 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Dec 18 | Feb 19 | May 10 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Jan 29 | Jan 29 | Apr 9 | 70 from sow |
| TomatilloToma Verde | Jan 1 | Feb 19 | Apr 30 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Jan 1 | Feb 19 | May 5 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Jan 1 | Feb 19 | May 10 | 80 from transplant |
Tight means first harvest lands within two weeks of the median first fall frost: start that crop indoors on time or cover it in fall.
What sauce can Napa grow?
Each sauce, scheduled for a Napa container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Napa frost questions
When is the last frost in Napa, CA?
The median last 32 °F freeze at NAPA STATE HOSPITAL, CA is February 12: half of years see a later one. One year in ten, a freeze still comes after March 13; nine years in ten, it comes after January 3. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Napa, CA?
The median first 32 °F freeze of fall is December 4. One year in ten it arrives before November 15; nine years in ten, before January 4 (next year).
How long is the growing season in Napa, CA?
299 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 257 days; one year in ten, at least 338 days.
What growing zone is Napa, CA?
USDA hardiness zone 9b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 94559. A zone describes the coldest winter night, not when frost ends, so it is the wrong number for a planting calendar — the frost dates on this page are the right one.
When should I plant tomatoes in Napa, CA?
Start Roma VF (determinate paste) seeds indoors around Jan 1 and transplant around Feb 19, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Mar 13. First ripe fruit lands around May 5.
When should I plant peppers in Napa, CA?
Sow jalapeño indoors on a heat mat around Dec 18; transplant no earlier than Feb 19, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around May 5.
Nearby in California
- Vallejolast frost Mar 5
- Fairfieldlast frost Jan 15
- Petalumalast frost Feb 28
- Vacavillelast frost Feb 18
- Novatolast frost Jan 11
- Rohnert Parklast frost Feb 28
All California frost dates → · How frost-date math drives a sowing calendar →