When to plant in San Anselmo, CA
USDA Zone 9bEverything below — frost dates, hardiness zone, and what to plant when in San Anselmo, California — is derived from the closest NOAA station with complete climate normals.
With about 344 frost-free days, San Anselmo supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. Zone 9b is warm enough that San Anselmo can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
The average last spring frost in San Anselmo is now 9 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
SAN RAFAEL CIVIC CTR · 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 Anselmo’s own odds, recorded at SAN RAFAEL CIVIC CTR.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 6 | Feb 22 | Jan 6 | Nov 15 | Dec 5 | Jan 1 |
| 32°F | Feb 25 | Jan 11 | Dec 14 | Dec 2 | Dec 21 | Feb 9 |
| 28°F | Feb 21 | Dec 31 | Dec 11 | Dec 7 | Dec 29 | Feb 18 |
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 Anselmo, 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 Anselmo planting FAQ
When is the last spring frost in San Anselmo, CA?
Plan for the last spring frost in San Anselmo around January 11 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in San Anselmo, CA?
The first fall frost in San Anselmo typically arrives around December 21 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is San Anselmo in?
San Anselmo is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.
How long is the growing season in San Anselmo?
There are roughly 344 frost-free days in San Anselmo (a long growing season), running from the average last frost around January 11 to the first fall frost near December 21.
When should I plant tomatoes in San Anselmo?
In San Anselmo, 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 Anselmo
An email when it’s time to start seeds, transplant, and sow — timed to San Anselmo’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- San Rafael · 6 km
- Larkspur · 6 km
- Corte Madera · 8 km
- Mill Valley · 9 km
- Novato · 12 km
- Tamalpais-Homestead Valley · 12 km
- Richmond · 19 km
- San Pablo · 20 km
Frost dates recorded at SAN RAFAEL CIVIC CTR, 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 Anselmo, CA — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00047880. Retrieved from https://blissgarden.com/california/san-anselmo.