When to plant in San Bruno, CA
USDA Zone 10aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for San Bruno, California — all computed from San Bruno's nearest NOAA weather station.
With only about -1 frost-free days, San Bruno has a short season — start heat-lovers indoors early, favor quick-maturing varieties, and use row cover to stretch both ends. Zone 10a is warm enough that San Bruno can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
The average last spring frost in San Bruno is now 5 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
PACIFICA 4 SSE · 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 Bruno’s own odds, recorded at PACIFICA 4 SSE.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 11 | Jan 25 | Dec 24 | Dec 1 | Jan 4 | Feb 19 |
| 32°F | Feb 12 | Jan 11 | Dec 23 | Dec 22 | Jan 10 | Feb 5 |
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 Bruno, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 13 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 Bruno planting FAQ
When is the last spring frost in San Bruno, CA?
On average, the last spring frost in San Bruno is around January 11 (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 San Bruno, CA?
In San Bruno, the first 32°F freeze of fall lands around January 10 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is San Bruno in?
San Bruno 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 Bruno?
There are roughly -1 frost-free days in San Bruno (a short growing season), running from the average last frost around January 11 to the first fall frost near January 10.
When should I plant tomatoes in San Bruno?
In San Bruno, start tomato seeds indoors around November 16–November 30, then transplant seedlings outdoors around January 18 once the danger of frost has passed.
Never miss a window in San Bruno
An email when it’s time to start seeds, transplant, and sow — timed to San Bruno’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Millbrae · 4 km
- Pacifica · 5 km
- South San Francisco · 6 km
- Burlingame · 7 km
- Daly City · 9 km
- Hillsborough · 10 km
- San Mateo · 13 km
- Belmont · 17 km
Frost dates recorded at PACIFICA 4 SSE, 5 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 Bruno, CA — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00046599. Retrieved from https://blissgarden.com/california/san-bruno.