When to plant in Palo Alto, CA
USDA Zone 9bPalo Alto, California frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Palo Alto enjoys a long ~309-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 9b, frost is a minor factor for Palo Alto — most perennials thrive, and annual vegetables can go out early and stay late.
The average last spring frost in Palo Alto is now 6 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
PALO ALTO · 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 Palo Alto’s own odds, recorded at PALO ALTO.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 15 | Mar 11 | Feb 5 | Nov 3 | Nov 21 | Dec 8 |
| 32°F | Mar 4 | Feb 1 | Dec 28 | Nov 20 | Dec 7 | Jan 6 |
| 28°F | Feb 17 | Jan 4 | Dec 15 | Dec 3 | Dec 22 | Jan 25 |
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 Palo Alto, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 10 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.
Palo Alto planting FAQ
When is the last spring frost in Palo Alto, CA?
Palo Alto's average last spring frost falls near February 1 — 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 Palo Alto, CA?
Expect Palo Alto's first fall frost near December 7 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Palo Alto in?
Palo Alto is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Palo Alto?
Palo Alto has about 309 frost-free days — a long growing season — between the average last spring frost (February 1) and first fall frost (December 7).
When should I plant tomatoes in Palo Alto?
For Palo Alto, sow tomatoes indoors about December 7–December 21 and move the seedlings out around February 8, after the last spring frost.
Never miss a window in Palo Alto
An email when it’s time to start seeds, transplant, and sow — timed to Palo Alto’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Stanford · 4 km
- Los Altos · 5 km
- Mountain View · 6 km
- East Palo Alto · 8 km
- Menlo Park · 9 km
- North Fair Oaks · 10 km
- Sunnyvale · 10 km
- Cupertino · 12 km
Frost dates recorded at PALO ALTO, 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 Palo Alto, CA — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00046646. Retrieved from https://blissgarden.com/california/palo-alto.