When to plant in La Mesa, CA
USDA Zone 10bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for La Mesa, California — all computed from La Mesa's nearest NOAA weather station.
La Mesa enjoys a long ~349-day frost-free season — you can succession-sow, fit in a second crop, and grow long-season heat-lovers with room to spare. In zone 10b, frost is a minor factor for La Mesa — most perennials thrive, and annual vegetables can go out early and stay late.
The average last spring frost in La Mesa is now 6 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
EL CAJON · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are La Mesa’s own odds, recorded at EL CAJON.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 3 | Feb 6 | Jan 6 | Nov 18 | Dec 6 | Dec 29 |
| 32°F | Feb 7 | Jan 6 | Dec 13 | Dec 1 | Dec 21 | Jan 15 |
| 28°F | Jan 15 | Dec 31 | Dec 8 | Dec 7 | Dec 30 | Jan 14 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Nothing new to sow or transplant outdoors in the next few weeks — a seasonal lull. Check the full-year calendar below for the next window.
Full-year planting calendar
Each bar is the exact window to take a planting action in La Mesa, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 23 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
La Mesa planting FAQ
When is the last spring frost in La Mesa, CA?
On average, the last spring frost in La Mesa is around January 6 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in La Mesa, CA?
The first fall frost in La Mesa typically arrives around December 21 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is La Mesa in?
La Mesa is in USDA hardiness zone 10b. In zone 10b, winters are mild — many tender perennials overwinter here.
How long is the growing season in La Mesa?
La Mesa has about 349 frost-free days — a long growing season — between the average last spring frost (January 6) and first fall frost (December 21).
When should I plant tomatoes in La Mesa?
For La Mesa, sow tomatoes indoors about November 11–November 25 and move the seedlings out around January 13, after the last spring frost.
Never miss a window in La Mesa
An email when it’s time to start seeds, transplant, and sow — timed to La Mesa’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Lemon Grove · 4 km
- Casa de Oro-Mount Helix · 5 km
- Spring Valley · 6 km
- La Presa · 7 km
- El Cajon · 7 km
- Bostonia · 9 km
- Rancho San Diego · 10 km
- Santee · 10 km
Frost dates recorded at EL CAJON, 9 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in La Mesa, CA — Frost Dates & Zone 10b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00042706. Retrieved from https://blissgarden.com/california/la-mesa.