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When to plant in Pleasant Hill, CA

USDA Zone 9b

Here are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Pleasant Hill, California — all computed from Pleasant Hill's nearest NOAA weather station.

Pleasant Hill 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. Zone 9b is warm enough that Pleasant Hill can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.

Station · CONCORD WWTP · 3.3 km
Last spring frost
January 7
50% chance · 32°F
First fall frost
December 19
50% chance · 32°F
Growing season
346 days
frost-free
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Frost calendar for Pleasant HillA year-band showing 32°F frost risk from January to December for Pleasant Hill: last spring frost around January 7, first fall frost around December 19, about 346 frost-free days between.
Shaded months carry frost risk; the clear span is the average frost-free season.

The average last spring frost in Pleasant Hill is now 7 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →

Frost probability

CONCORD WWTP · 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 Pleasant Hill’s own odds, recorded at CONCORD WWTP.

Frost-probability curves for Pleasant HillProbability of the last spring frost and first fall frost by date at 32°F. The last spring frost is most likely around January 7 and the first fall frost around December 19, giving about 346 frost-free days.
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 6Feb 9Jan 6Nov 15Dec 2Dec 24
32°FFeb 1Jan 7Dec 19Dec 1Dec 19Jan 12
28°FJan 20Dec 31Dec 14Dec 10Dec 29Jan 14

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 Pleasant Hill, drawn to the day from the local frost dates. The dashed line is today.

Nearby weather stations

3 within 7 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.

CONCORD WWTP
Primary
3 km · 12 m elevation
SPRING
Jan 7
FALL
Dec 19
CONCORD BUCHANAN FLD
5 km · 6 m elevation
SPRING
Jan 9
FALL
Dec 14
MARTINEZ WTP
7 km · 12 m elevation
SPRING
Feb 28
FALL
Nov 22

Pleasant Hill planting FAQ

When is the last spring frost in Pleasant Hill, CA?

On average, the last spring frost in Pleasant Hill is around January 7 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.

When is the first fall frost in Pleasant Hill, CA?

Expect Pleasant Hill'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 Pleasant Hill in?

Pleasant Hill is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.

How long is the growing season in Pleasant Hill?

There are roughly 346 frost-free days in Pleasant Hill (a long growing season), running from the average last frost around January 7 to the first fall frost near December 19.

When should I plant tomatoes in Pleasant Hill?

In Pleasant Hill, start tomato seeds indoors around November 12–November 26, then transplant seedlings outdoors around January 14 once the danger of frost has passed.

Planting reminders

Never miss a window in Pleasant Hill

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

Nearby cities

8 within reach

Frost dates recorded at CONCORD WWTP, 3 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 Pleasant Hill, CA — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00041967. Retrieved from https://blissgarden.com/california/pleasant-hill.
When to Plant in Pleasant Hill, CA — Frost Dates & Zone 9b — BlissGarden