Frost dates · USDA zone 10a
Frost dates for Simi Valley, CA
Simi Valley, CA sees its last 32 °F night of spring around January 24 and its first of fall around December 15 — a 329-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 21 (prior winter) | Jan 26 (next year) |
| Median — 1 year in 2 | Jan 24 | Dec 15 |
| 1 year in 10 | Mar 5 | Nov 27 |
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: 329 days median, at least 277 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 Dec 31 (prior winter) and first of Dec 26.
Simi Valley planting calendar, 2027
Every row runs from the median last frost (Jan 24) 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) | Nov 1 | Dec 27 | Apr 16 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Jan 24 | Feb 23 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Jan 10 | Jan 10 | Feb 24 | 45 from sow |
| Genovese BasilGenovese | Dec 27 | Feb 7 | Apr 8 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Nov 29 | Jan 31 | Apr 16 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Nov 15 | Feb 7 | May 13 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Nov 29 | Jan 31 | Apr 16 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Nov 29 | Jan 31 | Apr 21 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Nov 29 | Jan 31 | Apr 21 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Jan 10 | Jan 10 | Mar 21 | 70 from sow |
| TomatilloToma Verde | Dec 13 | Jan 31 | Apr 11 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Dec 13 | Jan 31 | Apr 16 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Dec 13 | Jan 31 | Apr 21 | 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 Simi Valley grow?
Each sauce, scheduled for a Simi Valley container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Simi Valley frost questions
When is the last frost in Simi Valley, CA?
The median last 32 °F freeze at WOODLAND HILLS PIERCE COLLEGE, CA is January 24: half of years see a later one. One year in ten, a freeze still comes after March 5; nine years in ten, it comes after December 21 (prior winter). Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Simi Valley, CA?
The median first 32 °F freeze of fall is December 15. One year in ten it arrives before November 27; nine years in ten, before January 26 (next year).
How long is the growing season in Simi Valley, CA?
329 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 277 days; one year in ten, no freeze at all.
What growing zone is Simi Valley, CA?
USDA hardiness zone 10a, per the 2023 USDA Plant Hardiness Zone Map for ZIP 93065. 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 Simi Valley, CA?
Start Roma VF (determinate paste) seeds indoors around Dec 13 and transplant around Jan 31, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Mar 5. First ripe fruit lands around Apr 16.
When should I plant peppers in Simi Valley, CA?
Sow jalapeño indoors on a heat mat around Nov 29; transplant no earlier than Jan 31, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Apr 16.
Nearby in California
- Thousand Oakslast frost Dec 31
- Camarillolast frost Dec 31
- Santa Claritalast frost Jan 8
- Santa Monicafrost rare
- Burbanklast frost Jan 2
- Los Angelesfrost rare
All California frost dates → · How frost-date math drives a sowing calendar →