When to plant in Walnut Creek, CA
USDA Zone 9bWalnut Creek, California frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Walnut Creek enjoys a long ~346-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 Walnut Creek — most perennials thrive, and annual vegetables can go out early and stay late.
The average last spring frost in Walnut Creek is now 7 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
CONCORD WWTP · 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 Walnut Creek’s own odds, recorded at CONCORD WWTP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 6 | Feb 9 | Jan 6 | Nov 15 | Dec 2 | Dec 24 |
| 32°F | Feb 1 | Jan 7 | Dec 19 | Dec 1 | Dec 19 | Jan 12 |
| 28°F | Jan 20 | Dec 31 | Dec 14 | Dec 10 | Dec 29 | Jan 14 |
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 Walnut Creek, 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.
Walnut Creek planting FAQ
When is the last spring frost in Walnut Creek, CA?
Plan for the last spring frost in Walnut Creek around January 7 (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 Walnut Creek, CA?
Expect Walnut Creek's first fall frost near December 19 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Walnut Creek in?
Walnut Creek is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Walnut Creek?
Walnut Creek has about 346 frost-free days — a long growing season — between the average last spring frost (January 7) and first fall frost (December 19).
When should I plant tomatoes in Walnut Creek?
For Walnut Creek, sow tomatoes indoors about November 12–November 26 and move the seedlings out around January 14, after the last spring frost.
Never miss a window in Walnut Creek
An email when it’s time to start seeds, transplant, and sow — timed to Walnut Creek’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at CONCORD WWTP, 9 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 Walnut Creek, CA — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00041967. Retrieved from https://blissgarden.com/california/walnut-creek.