When to plant in American Canyon, CA
USDA Zone 9bEverything below — frost dates, hardiness zone, and what to plant when in American Canyon, California — is derived from the closest NOAA station with complete climate normals.
A generous ~261-day season lets American Canyon gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. Zone 9b is warm enough that American Canyon can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
The average last spring frost in American Canyon is now 21 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
NAPA CO 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 American Canyon’s own odds, recorded at NAPA CO AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 9 | Apr 17 | Mar 17 | Oct 16 | Nov 4 | Nov 22 |
| 32°F | Apr 16 | Mar 5 | Jan 26 | Nov 3 | Nov 21 | Dec 13 |
| 28°F | Feb 28 | Jan 23 | Dec 20 | Nov 16 | Dec 5 | Jan 11 |
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 American Canyon, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 11 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.
American Canyon planting FAQ
When is the last spring frost in American Canyon, CA?
Plan for the last spring frost in American Canyon around March 5 (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 American Canyon, CA?
In American Canyon, the first 32°F freeze of fall lands around November 21 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is American Canyon in?
American Canyon is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.
How long is the growing season in American Canyon?
There are roughly 261 frost-free days in American Canyon (a long growing season), running from the average last frost around March 5 to the first fall frost near November 21.
When should I plant tomatoes in American Canyon?
In American Canyon, start tomato seeds indoors around January 8–January 22, then transplant seedlings outdoors around March 12 once the danger of frost has passed.
Never miss a window in American Canyon
An email when it’s time to start seeds, transplant, and sow — timed to American Canyon’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at NAPA CO AP, 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 American Canyon, CA — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00093227. Retrieved from https://blissgarden.com/california/american-canyon.