Frost dates 2026–2027

Frost dates for Pleasant Hill, California

Median (50% chance) dates of the last and first 32°F frost, from NOAA 1991–2020 climate normals at Concord Wastewater Plant, 2.1 mi away (close match).

Last spring frostJan 7
First fall frostDec 19
346 frost-free days
Last spring frostJan 71 year in 10 after Feb 1
First fall frostDec 191 year in 10 by Dec 1
Growing season346 daysbetween median 32°F dates
Hardiness zoneZone 9b25 to 30°F average extreme low

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Will it freeze in Pleasant Hill in the next 7 nights?

No overnight lows at or below 32°F are forecast in Pleasant Hill during the next 7 nights in the available NWS frost forecast.

Tonight: forecast low 49°F. Above 36°F.

NWS forecast period: Thu, Nov 5, 6:00 PM PST to Fri, Nov 6, 6:00 AM PST.

No nights at or below 36°F in the National Weather Service forecast for the next 7 nights.

Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.

Frost and freeze probabilities

Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.

These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.

Average first hard freeze in Pleasant Hill

Most years have no 28°F hard freeze at Concord Wastewater Plant, according to NOAA’s 1991–2020 Climate Normals. Check the short-term forecast above during cold snaps.

TemperatureLast spring date
90% · 50% · 10% chance of a later freeze
First fall date
10% · 50% · 90% chance of an earlier freeze
Season
36°F frost possible Jan 6 · Feb 9 · Mar 6 Nov 15 · Dec 2 · Dec 24 297 days
32°F freeze Dec 19 · Jan 7 · Feb 1 Dec 1 · Dec 19 · Jan 12 346 days
28°F hard freeze Dec 14 · Dec 31 · Jan 20 Dec 10 · Dec 29 · Jan 14 365 days
NOAA NCEI U.S. Climate Normals 1991–2020, station USC00041967. How to read these probabilities.

Average high temperature by month

1991–2020 normals at Concord Wastewater Plant

Average low temperature by month

Months with lows near or below freezing carry frost risk

Where these frost dates come from

The frost dates for Pleasant Hill, CA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Concord Wastewater Plant (station USC00041967, elevation 40 ft), 2.1 mi from Pleasant Hill. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.

Frost dates near Pleasant Hill

CityDistanceLast spring frostFirst fall frost
Martinez, CA 3.7 mi Feb 28 Nov 22
Walnut Creek, CA 4.3 mi Jan 7 Dec 19
Concord, CA 4.3 mi Jan 9 Dec 14
Lafayette, CA 5.0 mi Jan 7 Dec 19
Orinda, CA 6.8 mi rare rare
Moraga, CA 8.1 mi rare rare
Clayton, CA 8.1 mi Mar 8 Dec 22
Benicia, CA 9.3 mi Jan 17 Dec 27
Pittsburg, CA 11 mi Jan 12 Dec 19
Danville, CA 11 mi Mar 8 Dec 22

Frequently asked questions

When is the last frost in Pleasant Hill?

On average, the last spring frost (32°F) in Pleasant Hill is around January 7. In about 1 year in 10 it comes after February 1, and in 9 years in 10 it comes after December 19.

When is the first frost in Pleasant Hill?

The first fall frost (32°F) usually arrives around December 19. There’s a 10% chance of a freeze by December 1 and a 90% chance by January 12.

Can it frost in Pleasant Hill after the last frost date?

Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after February 9.

What growing zone is Pleasant Hill?

Pleasant Hill is in USDA Plant Hardiness Zone 9b (average annual extreme minimum temperature 25 to 30°F), based on the 2023 USDA map for ZIP code 94523. See growing zones in California.

More: all California frost dates · California growing zones · UV index today in Pleasant Hill · frost vs. freeze