When to plant in Placentia, CA
USDA Zone 10bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Placentia, California — all computed from Placentia's nearest NOAA weather station.
A generous ~354-day season lets Placentia gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. Placentia's nearest full-normals station sits about 22 km out, so treat these as a close estimate — local microclimate can nudge your first and last frost. Zone 10b is warm enough that Placentia can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
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 Placentia’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 Placentia, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 24 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.
Placentia planting FAQ
When is the last spring frost in Placentia, CA?
Placentia'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 Placentia, CA?
The first fall frost in Placentia typically arrives around December 25 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Placentia in?
Placentia is in USDA hardiness zone 10b. In zone 10b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Placentia?
There are roughly 354 frost-free days in Placentia (a long growing season), running from the average last frost around January 5 to the first fall frost near December 25.
When should I plant tomatoes in Placentia?
In Placentia, start tomato seeds indoors around November 10–November 24, then transplant seedlings outdoors around January 12 once the danger of frost has passed.
Never miss a window in Placentia
An email when it’s time to start seeds, transplant, and sow — timed to Placentia’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Brea · 5 km
- Fullerton · 7 km
- Yorba Linda · 8 km
- Anaheim · 9 km
- La Habra · 10 km
- Rowland Heights · 10 km
- Orange · 10 km
- Chino Hills · 14 km
Frost dates recorded at TUSTIN IRVINE RCH, 22 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 Placentia, CA — Frost Dates & Zone 10b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00049087. Retrieved from https://blissgarden.com/california/placentia.