When to plant in Petaluma, CA
USDA Zone 9bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Petaluma, California — all computed from Petaluma's nearest NOAA weather station.
A generous ~270-day season lets Petaluma gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. In zone 9b, frost is a minor factor for Petaluma — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
PETALUMA AP · 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 Petaluma’s own odds, recorded at PETALUMA AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 27 | Apr 6 | Mar 7 | Oct 27 | Nov 10 | Nov 28 |
| 32°F | Apr 6 | Feb 28 | Jan 24 | Nov 9 | Nov 25 | Dec 16 |
| 28°F | Feb 24 | Jan 17 | Dec 17 | Nov 20 | Dec 9 | Jan 12 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Petaluma, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 25 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.
Petaluma planting FAQ
When is the last spring frost in Petaluma, CA?
Plan for the last spring frost in Petaluma around February 28 (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 Petaluma, CA?
In Petaluma, the first 32°F freeze of fall lands around November 25 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Petaluma in?
Petaluma is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Petaluma?
Petaluma has about 270 frost-free days — a long growing season — between the average last spring frost (February 28) and first fall frost (November 25).
When should I plant tomatoes in Petaluma?
For Petaluma, sow tomatoes indoors about January 3–January 17 and move the seedlings out around March 7, after the last spring frost.
Never miss a window in Petaluma
An email when it’s time to start seeds, transplant, and sow — timed to Petaluma’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Rohnert Park · 13 km
- Sonoma · 16 km
- Novato · 19 km
- Santa Rosa · 24 km
- Napa · 29 km
- San Anselmo · 29 km
- San Rafael · 31 km
- American Canyon · 33 km
Frost dates recorded at PETALUMA AP, 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 Petaluma, CA — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00046826. Retrieved from https://blissgarden.com/california/petaluma.