When to plant in San Lorenzo, CA
USDA Zone 10aSan Lorenzo, California frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
San Lorenzo enjoys a long ~357-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 10a, frost is a minor factor for San Lorenzo — most perennials thrive, and annual vegetables can go out early and stay late.
The average first fall frost in San Lorenzo is now 5 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
HAYWARD AIR TERMINAL · 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 San Lorenzo’s own odds, recorded at HAYWARD AIR TERMINAL.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Feb 28 | Jan 29 | Dec 30 | Nov 24 | Dec 12 | Jan 11 |
| 32°F | Jan 27 | Jan 2 | Dec 13 | Dec 6 | Dec 25 | Jan 20 |
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 San Lorenzo, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 18 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.
San Lorenzo planting FAQ
When is the last spring frost in San Lorenzo, CA?
San Lorenzo's average last spring frost falls near January 2 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in San Lorenzo, CA?
The first fall frost in San Lorenzo typically arrives around December 25 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is San Lorenzo in?
San Lorenzo is in USDA hardiness zone 10a. In zone 10a, winters are mild — many tender perennials overwinter here.
How long is the growing season in San Lorenzo?
San Lorenzo has about 357 frost-free days — a long growing season — between the average last spring frost (January 2) and first fall frost (December 25).
When should I plant tomatoes in San Lorenzo?
For San Lorenzo, sow tomatoes indoors about November 7–November 21 and move the seedlings out around January 9, after the last spring frost.
Never miss a window in San Lorenzo
An email when it’s time to start seeds, transplant, and sow — timed to San Lorenzo’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Ashland · 3 km
- Cherryland · 3 km
- San Leandro · 4 km
- Hayward · 6 km
- Castro Valley · 7 km
- Fairview · 8 km
- Oakland · 13 km
- Union City · 13 km
Frost dates recorded at HAYWARD AIR TERMINAL, 3 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 San Lorenzo, CA — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00093228. Retrieved from https://blissgarden.com/california/san-lorenzo.