Frost dates · USDA zone 9b
Frost dates for San Ramon, CA
San Ramon, CA sees its last 32 °F night of spring around February 15 and its first of fall around December 2 — a 292-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 12 | Dec 28 |
| Median — 1 year in 2 | Feb 15 | Dec 2 |
| 1 year in 10 | Mar 13 | Nov 16 |
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: 292 days median, at least 257 in 9 years of 10, at least 330 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 10 and first of Dec 18.
San Ramon planting calendar, 2027
Every row runs from the median last frost (Feb 15) and median first frost (Dec 2) 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 23 | Jan 18 | May 8 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Feb 15 | Mar 17 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Feb 1 | Feb 1 | Mar 18 | 45 from sow |
| Genovese BasilGenovese | Jan 18 | Mar 1 | Apr 30 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Dec 21 | Feb 22 | May 8 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Dec 7 | Mar 1 | Jun 4 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Dec 21 | Feb 22 | May 8 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Dec 21 | Feb 22 | May 13 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Dec 21 | Feb 22 | May 13 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Feb 1 | Feb 1 | Apr 12 | 70 from sow |
| TomatilloToma Verde | Jan 4 | Feb 22 | May 3 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Jan 4 | Feb 22 | May 8 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Jan 4 | Feb 22 | May 13 | 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 San Ramon grow?
Each sauce, scheduled for a San Ramon container garden: when the first seeds go in and when enough fruit has ripened for one batch.
San Ramon frost questions
When is the last frost in San Ramon, CA?
The median last 32 °F freeze at LIVERMORE, CA is February 15: 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 12. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in San Ramon, CA?
The median first 32 °F freeze of fall is December 2. One year in ten it arrives before November 16; nine years in ten, before December 28.
How long is the growing season in San Ramon, CA?
292 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 330 days.
What growing zone is San Ramon, CA?
USDA hardiness zone 9b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 94582. 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 San Ramon, CA?
Start Roma VF (determinate paste) seeds indoors around Jan 4 and transplant around Feb 22, 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 8.
When should I plant peppers in San Ramon, CA?
Sow jalapeño indoors on a heat mat around Dec 21; transplant no earlier than Feb 22, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around May 8.
Nearby in California
- Danvillelast frost Mar 8
- Dublinlast frost Feb 15
- Pleasantonlast frost Feb 15
- Livermorelast frost Feb 15
- Walnut Creeklast frost Mar 8
- Union Citylast frost Jan 2
All California frost dates → · How frost-date math drives a sowing calendar →