Frost dates · USDA zone 9b
Frost dates for Cupertino, CA
Cupertino, CA sees its last 32 °F night of spring around March 21 and its first of fall around December 15 — a 275-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 19 | Jan 30 (next year) |
| Median — 1 year in 2 | Mar 21 | Dec 15 |
| 1 year in 10 | Apr 28 | Nov 21 |
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: 275 days median, at least 227 in 9 years of 10, at least 337 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 29 and first of Jan 4 (next year).
Cupertino planting calendar, 2027
Every row runs from the median last frost (Mar 21) and median first frost (Dec 15) 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 27 | Feb 21 | Jun 11 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Mar 21 | Apr 20 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Mar 7 | Mar 7 | Apr 21 | 45 from sow |
| Genovese BasilGenovese | Feb 21 | Apr 4 | Jun 3 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Jan 24 | Mar 28 | Jun 11 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Jan 10 | Apr 4 | Jul 8 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Jan 24 | Mar 28 | Jun 11 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Jan 24 | Mar 28 | Jun 16 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Jan 24 | Mar 28 | Jun 16 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Mar 7 | Mar 7 | May 16 | 70 from sow |
| TomatilloToma Verde | Feb 7 | Mar 28 | Jun 6 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Feb 7 | Mar 28 | Jun 11 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Feb 7 | Mar 28 | Jun 16 | 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 Cupertino grow?
Each sauce, scheduled for a Cupertino container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Cupertino frost questions
When is the last frost in Cupertino, CA?
The median last 32 °F freeze at SKYLINE RIDGE PRESERVE, CA is March 21: half of years see a later one. One year in ten, a freeze still comes after April 28; nine years in ten, it comes after January 19. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Cupertino, CA?
The median first 32 °F freeze of fall is December 15. One year in ten it arrives before November 21; nine years in ten, before January 30 (next year).
How long is the growing season in Cupertino, CA?
275 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 227 days; one year in ten, at least 337 days.
What growing zone is Cupertino, CA?
USDA hardiness zone 9b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 95014. 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 Cupertino, CA?
Start Roma VF (determinate paste) seeds indoors around Feb 7 and transplant around Mar 28, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Apr 28. First ripe fruit lands around Jun 11.
When should I plant peppers in Cupertino, CA?
Sow jalapeño indoors on a heat mat around Jan 24; transplant no earlier than Mar 28, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jun 11.
Nearby in California
- Sunnyvalelast frost Jan 6
- Santa Claralast frost Jan 12
- Campbelllast frost Feb 2
- Mountain Viewlast frost Jan 6
- Palo Altolast frost Feb 1
- Milpitaslast frost Jan 12
All California frost dates → · How frost-date math drives a sowing calendar →