When to plant in Westminster, CA
USDA Zone 10aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Westminster, California — all computed from Westminster's nearest NOAA weather station.
A generous ~354-day season lets Westminster gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. These dates come from a station roughly 23 km away, the closest with full normals; terrain around Westminster (elevation, water, pavement) can move your real frost dates a few days either way. In zone 10a, frost is a minor factor for Westminster — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
TUSTIN IRVINE RCH · 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 Westminster’s own odds, recorded at TUSTIN IRVINE RCH.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 5 | Feb 1 | Jan 3 | Nov 24 | Dec 13 | Jan 8 |
| 32°F | Feb 2 | Jan 5 | Dec 14 | Dec 3 | Dec 25 | Jan 20 |
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 Westminster, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 33 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.
Westminster planting FAQ
When is the last spring frost in Westminster, CA?
Westminster's average last spring frost falls near January 5 — 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 Westminster, CA?
The first fall frost in Westminster typically arrives around December 25 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Westminster in?
Westminster is in USDA hardiness zone 10a. In zone 10a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Westminster?
Westminster has about 354 frost-free days — a long growing season — between the average last spring frost (January 5) and first fall frost (December 25).
When should I plant tomatoes in Westminster?
For Westminster, sow tomatoes indoors about November 10–November 24 and move the seedlings out around January 12, after the last spring frost.
Never miss a window in Westminster
An email when it’s time to start seeds, transplant, and sow — timed to Westminster’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Garden Grove · 4 km
- Stanton · 5 km
- Fountain Valley · 6 km
- Huntington Beach · 6 km
- Seal Beach · 7 km
- Los Alamitos · 8 km
- Cypress · 8 km
- Rossmoor · 9 km
Frost dates recorded at TUSTIN IRVINE RCH, 23 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 Westminster, CA — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00049087. Retrieved from https://blissgarden.com/california/westminster.