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When to plant in Willowbrook, CA

USDA Zone 10b

Everything below — frost dates, hardiness zone, and what to plant when in Willowbrook, California — is derived from the closest NOAA station with complete climate normals.

Willowbrook's growing season is short at roughly -4 days, so succession planting is limited; lean on transplants over direct sowing for anything slow to mature. These dates come from a station roughly 16 km away, the closest with full normals; terrain around Willowbrook (elevation, water, pavement) can move your real frost dates a few days either way. In zone 10b, frost is a minor factor for Willowbrook — most perennials thrive, and annual vegetables can go out early and stay late.

Station · TORRANCE AP · 16.4 km
Last spring frost
January 9
50% chance · 32°F
First fall frost
January 5
50% chance · 32°F
Growing season
-4 days
frost-free
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Frost calendar for WillowbrookA year-band from January to December for Willowbrook: Willowbrook is effectively frost-free at 32°F — no distinct frost season.
Willowbrook is effectively frost-free at 32°F — no distinct frost season.

Frost probability

TORRANCE AP · 1991–2020

The 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 Willowbrook’s own odds, recorded at TORRANCE AP.

Frost-probability curves for WillowbrookProbability of the last spring frost and first fall frost by date at 32°F. The last spring frost is most likely around January 9 and the first fall frost around January 5, where a 32°F freeze is rare enough that there is effectively no distinct frost season.
Last spring frostFirst fall frostbold = 32°F · thin = 28°F / 36°F · dot = 50% date · band = 10–90% window
ThresholdSPRING 10%SPRING 50%SPRING 90%FALL 10%FALL 50%FALL 90%
36°FMar 5Jan 17Dec 12Dec 1Dec 31Feb 20
32°FFeb 24Jan 9Dec 4Dec 3Jan 5Feb 22

Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.

What to plant now

TODAY · JULY 19

Nothing new to sow or transplant outdoors in the next few weeks — a seasonal lull. Check the full-year calendar below for the next window.

Add the next planting windows to your calendar (.ics) ↓

Full-year planting calendar

Start indoorsTransplantDirect sowFall sow

Each bar is the exact window to take a planting action in Willowbrook, drawn to the day from the local frost dates. The dashed line is today.

Nearby weather stations

3 within 27 km · complete 32°F normals

When 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.

TORRANCE AP
Primary
16 km · 27 m elevation
SPRING
Jan 9
FALL
Jan 5
SAN GABRIEL FIRE DEPT
22 km · 111 m elevation
SPRING
Jan 4
FALL
Jan 2
PASADENA
27 km · 263 m elevation
SPRING
Jan 8
FALL
Jan 7

Willowbrook planting FAQ

When is the last spring frost in Willowbrook, CA?

Willowbrook's average last spring frost falls near January 9 — 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 Willowbrook, CA?

In Willowbrook, the first 32°F freeze of fall lands around January 5 on average. Time your last harvests and any season-extension cover before it.

What hardiness zone is Willowbrook in?

Willowbrook is in USDA hardiness zone 10b. In zone 10b, winters are mild — many tender perennials overwinter here.

How long is the growing season in Willowbrook?

Willowbrook has about -4 frost-free days — a short growing season — between the average last spring frost (January 9) and first fall frost (January 5).

When should I plant tomatoes in Willowbrook?

For Willowbrook, sow tomatoes indoors about November 14–November 28 and move the seedlings out around January 16, after the last spring frost.

Planting reminders

Never miss a window in Willowbrook

An email when it’s time to start seeds, transplant, and sow — timed to Willowbrook’s frost dates. Double opt-in, one-click unsubscribe, no spam.

Nearby cities

8 within reach

Frost dates recorded at TORRANCE AP, 16 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.

Cite this page
BlissGarden. "When to Plant in Willowbrook, CA — Frost Dates & Zone 10b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00003122. Retrieved from https://blissgarden.com/california/willowbrook.
When to Plant in Willowbrook, CA — Frost Dates & Zone 10b — BlissGarden