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When to plant in Imperial Beach, CA

USDA Zone 10b

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

Imperial Beach enjoys a long ~359-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 10b, frost is a minor factor for Imperial Beach — most perennials thrive, and annual vegetables can go out early and stay late.

Station · SAN DIEGO BROWN FLD · 12.7 km
Last spring frost
January 6
50% chance · 32°F
First fall frost
December 31
50% chance · 32°F
Growing season
359 days
frost-free
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Frost calendar for Imperial BeachA year-band showing 32°F frost risk from January to December for Imperial Beach: last spring frost around January 6, first fall frost around December 31, about 359 frost-free days between.
Shaded months carry frost risk; the clear span is the average frost-free season.

Frost probability

SAN DIEGO BROWN FLD · 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 Imperial Beach’s own odds, recorded at SAN DIEGO BROWN FLD.

Frost-probability curves for Imperial BeachProbability of the last spring frost and first fall frost by date at 32°F. The last spring frost is most likely around January 6 and the first fall frost around December 31, giving about 359 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 7Feb 2Dec 29Dec 1Dec 20Jan 25
32°FFeb 5Jan 6Dec 13Dec 11Dec 31Jan 30

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 Imperial Beach, drawn to the day from the local frost dates. The dashed line is today.

Nearby weather stations

3 within 44 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.

SAN DIEGO BROWN FLD
Primary
13 km · 157 m elevation
SPRING
Jan 6
FALL
Dec 31
EL CAJON
31 km · 151 m elevation
SPRING
Jan 6
FALL
Dec 21
ALPINE
44 km · 517 m elevation
SPRING
Feb 12
FALL
Dec 24

Imperial Beach planting FAQ

When is the last spring frost in Imperial Beach, CA?

On average, the last spring frost in Imperial Beach is around January 6 (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 Imperial Beach, CA?

Expect Imperial Beach's first fall frost near December 31 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.

What hardiness zone is Imperial Beach in?

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

How long is the growing season in Imperial Beach?

Imperial Beach has about 359 frost-free days — a long growing season — between the average last spring frost (January 6) and first fall frost (December 31).

When should I plant tomatoes in Imperial Beach?

For Imperial Beach, sow tomatoes indoors about November 11–November 25 and move the seedlings out around January 13, after the last spring frost.

Planting reminders

Never miss a window in Imperial Beach

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

Nearby cities

8 within reach

Frost dates recorded at SAN DIEGO BROWN FLD, 13 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 Imperial Beach, CA — Frost Dates & Zone 10b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00003178. Retrieved from https://blissgarden.com/california/imperial-beach.
When to Plant in Imperial Beach, CA — Frost Dates & Zone 10b — BlissGarden