Frost dates · USDA zone 9b
Frost dates for Petaluma, CA
Petaluma, CA sees its last 32 °F night of spring around February 28 and its first of fall around November 25 — a 271-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 24 | Dec 16 |
| Median — 1 year in 2 | Feb 28 | Nov 25 |
| 1 year in 10 | Apr 6 | Nov 9 |
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: 271 days median, at least 230 in 9 years of 10, at least 313 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 17 and first of Dec 9.
Petaluma planting calendar, 2027
Every row runs from the median last frost (Feb 28) and median first frost (Nov 25) 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) | Dec 6 | Jan 31 | May 21 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Feb 28 | Mar 30 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Feb 14 | Feb 14 | Mar 31 | 45 from sow |
| Genovese BasilGenovese | Jan 31 | Mar 14 | May 13 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Jan 3 | Mar 7 | May 21 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Dec 20 | Mar 14 | Jun 17 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Jan 3 | Mar 7 | May 21 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Jan 3 | Mar 7 | May 26 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Jan 3 | Mar 7 | May 26 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Feb 14 | Feb 14 | Apr 25 | 70 from sow |
| TomatilloToma Verde | Jan 17 | Mar 7 | May 16 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Jan 17 | Mar 7 | May 21 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Jan 17 | Mar 7 | May 26 | 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 Petaluma grow?
Each sauce, scheduled for a Petaluma container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Petaluma frost questions
When is the last frost in Petaluma, CA?
The median last 32 °F freeze at PETALUMA AP, CA is February 28: half of years see a later one. One year in ten, a freeze still comes after April 6; nine years in ten, it comes after January 24. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Petaluma, CA?
The median first 32 °F freeze of fall is November 25. One year in ten it arrives before November 9; nine years in ten, before December 16.
How long is the growing season in Petaluma, CA?
271 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 230 days; one year in ten, at least 313 days.
What growing zone is Petaluma, CA?
USDA hardiness zone 9b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 94954. 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 Petaluma, CA?
Start Roma VF (determinate paste) seeds indoors around Jan 17 and transplant around Mar 7, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Apr 6. First ripe fruit lands around May 21.
When should I plant peppers in Petaluma, CA?
Sow jalapeño indoors on a heat mat around Jan 3; transplant no earlier than Mar 7, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around May 21.
Nearby in California
- Rohnert Parklast frost Feb 28
- Novatolast frost Jan 11
- Santa Rosalast frost Feb 25
- Napalast frost Feb 12
- San Rafaellast frost Jan 11
- Vallejolast frost Mar 5
All California frost dates → · How frost-date math drives a sowing calendar →