Frost dates · USDA zone 9b
Frost dates for Brentwood, CA
Brentwood, CA sees its last 32 °F night of spring around January 12 and its first of fall around December 19 — a 343-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 | Dec 20 (prior winter) | Jan 12 (next year) |
| Median — 1 year in 2 | Jan 12 | Dec 19 |
| 1 year in 10 | Feb 1 | Nov 29 |
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: 343 days median, at least 315 in 9 years of 10, no freeze at all 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 2 and first of Dec 29.
Brentwood planting calendar, 2027
Every row runs from the median last frost (Jan 12) and median first frost (Dec 19) 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) | Oct 20 | Dec 15 | Apr 4 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Jan 12 | Feb 11 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Dec 29 | Dec 29 | Feb 12 | 45 from sow |
| Genovese BasilGenovese | Dec 15 | Jan 26 | Mar 27 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Nov 17 | Jan 19 | Apr 4 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Nov 3 | Jan 26 | May 1 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Nov 17 | Jan 19 | Apr 4 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Nov 17 | Jan 19 | Apr 9 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Nov 17 | Jan 19 | Apr 9 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Dec 29 | Dec 29 | Mar 9 | 70 from sow |
| TomatilloToma Verde | Dec 1 | Jan 19 | Mar 30 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Dec 1 | Jan 19 | Apr 4 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Dec 1 | Jan 19 | Apr 9 | 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 Brentwood grow?
Each sauce, scheduled for a Brentwood container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Brentwood frost questions
When is the last frost in Brentwood, CA?
The median last 32 °F freeze at ANTIOCH PUMPING PLT #3, CA is January 12: half of years see a later one. One year in ten, a freeze still comes after February 1; nine years in ten, it comes after December 20 (prior winter). Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Brentwood, CA?
The median first 32 °F freeze of fall is December 19. One year in ten it arrives before November 29; nine years in ten, before January 12 (next year).
How long is the growing season in Brentwood, CA?
343 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 315 days; one year in ten, no freeze at all.
What growing zone is Brentwood, CA?
USDA hardiness zone 9b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 94513. 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 Brentwood, CA?
Start Roma VF (determinate paste) seeds indoors around Dec 1 and transplant around Jan 19, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Feb 1. First ripe fruit lands around Apr 4.
When should I plant peppers in Brentwood, CA?
Sow jalapeño indoors on a heat mat around Nov 17; transplant no earlier than Jan 19, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Apr 4.
Nearby in California
- Oakleylast frost Jan 12
- Antiochlast frost Jan 12
- Pittsburglast frost Jan 9
- Concordlast frost Jan 9
- Danvillelast frost Mar 8
- San Ramonlast frost Feb 15
All California frost dates → · How frost-date math drives a sowing calendar →