Frost dates · USDA zone 10b
Frost dates for La Mesa, CA
La Mesa, CA sees its last 32 °F night of spring around January 6 and its first of fall around December 21 — a 350-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 13 (prior winter) | Jan 15 (next year) |
| Median — 1 year in 2 | Jan 6 | Dec 21 |
| 1 year in 10 | Feb 7 | Dec 1 |
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: 350 days median, at least 317 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 30.
La Mesa planting calendar, 2027
Every row runs from the median last frost (Jan 6) and median first frost (Dec 21) 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 14 | Dec 9 | Mar 29 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Jan 6 | Feb 5 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Dec 23 | Dec 23 | Feb 6 | 45 from sow |
| Genovese BasilGenovese | Dec 9 | Jan 20 | Mar 21 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Nov 11 | Jan 13 | Mar 29 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Oct 28 | Jan 20 | Apr 25 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Nov 11 | Jan 13 | Mar 29 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Nov 11 | Jan 13 | Apr 3 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Nov 11 | Jan 13 | Apr 3 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Dec 23 | Dec 23 | Mar 3 | 70 from sow |
| TomatilloToma Verde | Nov 25 | Jan 13 | Mar 24 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Nov 25 | Jan 13 | Mar 29 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Nov 25 | Jan 13 | Apr 3 | 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 La Mesa grow?
Each sauce, scheduled for a La Mesa container garden: when the first seeds go in and when enough fruit has ripened for one batch.
La Mesa frost questions
When is the last frost in La Mesa, CA?
The median last 32 °F freeze at EL CAJON, CA is January 6: half of years see a later one. One year in ten, a freeze still comes after February 7; nine years in ten, it comes after December 13 (prior winter). Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in La Mesa, CA?
The median first 32 °F freeze of fall is December 21. One year in ten it arrives before December 1; nine years in ten, before January 15 (next year).
How long is the growing season in La Mesa, CA?
350 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 317 days; one year in ten, no freeze at all.
What growing zone is La Mesa, CA?
USDA hardiness zone 10b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 91942. 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 La Mesa, CA?
Start Roma VF (determinate paste) seeds indoors around Nov 25 and transplant around Jan 13, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Feb 7. First ripe fruit lands around Mar 29.
When should I plant peppers in La Mesa, CA?
Sow jalapeño indoors on a heat mat around Nov 11; transplant no earlier than Jan 13, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Mar 29.
Nearby in California
- El Cajonlast frost Jan 6
- Santeelast frost Jan 6
- San Diegofrost rare
- National Cityfrost rare
- Chula Vistalast frost Jan 6
- Powaylast frost Mar 4
All California frost dates → · How frost-date math drives a sowing calendar →