When to plant in San Carlos, CA
USDA Zone 10aEverything below — frost dates, hardiness zone, and what to plant when in San Carlos, California — is derived from the closest NOAA station with complete climate normals.
With about 329 frost-free days, San Carlos supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. In zone 10a, frost is a minor factor for San Carlos — most perennials thrive, and annual vegetables can go out early and stay late.
The average last spring frost in San Carlos is now 6 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
REDWOOD CITY · 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 Carlos’s own odds, recorded at REDWOOD CITY.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 31 | Feb 25 | Jan 25 | Nov 8 | Nov 25 | Dec 14 |
| 32°F | Feb 16 | Jan 17 | Dec 20 | Nov 24 | Dec 12 | Jan 14 |
| 28°F | Jan 22 | Dec 31 | Dec 14 | Dec 5 | Dec 26 | Jan 15 |
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 Carlos, 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 Carlos planting FAQ
When is the last spring frost in San Carlos, CA?
San Carlos's average last spring frost falls near January 17 — 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 Carlos, CA?
Expect San Carlos's first fall frost near December 12 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is San Carlos in?
San Carlos 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 Carlos?
San Carlos has about 329 frost-free days — a long growing season — between the average last spring frost (January 17) and first fall frost (December 12).
When should I plant tomatoes in San Carlos?
For San Carlos, sow tomatoes indoors about November 22–December 6 and move the seedlings out around January 24, after the last spring frost.
Never miss a window in San Carlos
An email when it’s time to start seeds, transplant, and sow — timed to San Carlos’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Belmont · 3 km
- Redwood City · 5 km
- North Fair Oaks · 6 km
- Foster City · 7 km
- San Mateo · 8 km
- Hillsborough · 10 km
- Menlo Park · 11 km
- Stanford · 12 km
Frost dates recorded at REDWOOD CITY, 4 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 Carlos, CA — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00047339. Retrieved from https://blissgarden.com/california/san-carlos.