Frost dates 2026–2027

Frost dates for Clayton, California

Median (50% chance) dates of the last and first 32°F frost, from NOAA 1991–2020 climate normals at Mt Diablo Junction, 4.2 mi away (close match).

Last spring frostMar 8
First fall frostDec 22
282 frost-free days
Last spring frostMar 81 year in 10 after Apr 15
First fall frostDec 221 year in 10 by Nov 23
Growing season282 daysbetween median 32°F dates
Hardiness zoneZone 9b25 to 30°F average extreme low

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Will it freeze in Clayton in the next 7 nights?

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

Tonight: forecast low 47°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 Clayton

The median first fall hard-freeze date (28°F) is January 16, from NOAA’s 1991–2020 Climate Normals at Mt Diablo Junction. This is the 50% probability date, not a forecast for this year.

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 Mar 16 · Apr 19 · May 20 Nov 6 · Nov 29 · Dec 20 221 days
32°F freeze Jan 12 · Mar 8 · Apr 15 Nov 23 · Dec 22 · Feb 11 282 days
28°F hard freeze Dec 21 · Feb 8 · Mar 23 Dec 8 · Jan 16 · Mar 3 364 days
NOAA NCEI U.S. Climate Normals 1991–2020, station USC00045915. How to read these probabilities.

Average high temperature by month

1991–2020 normals at Mt Diablo Junction

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 Clayton, CA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Mt Diablo Junction (station USC00045915, elevation 2,170 ft), 4.2 mi from Clayton. 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 Clayton

CityDistanceLast spring frostFirst fall frost
Concord, CA 4.3 mi Jan 9 Dec 14
Pittsburg, CA 5.6 mi Jan 12 Dec 19
Walnut Creek, CA 6.8 mi Jan 7 Dec 19
Antioch, CA 7.5 mi Jan 12 Dec 19
Pleasant Hill, CA 8.1 mi Jan 7 Dec 19
Danville, CA 9.3 mi Mar 8 Dec 22
Martinez, CA 11 mi Feb 28 Nov 22
Lafayette, CA 11 mi Jan 7 Dec 19
Brentwood, CA 12 mi Jan 12 Dec 19
San Ramon, CA 12 mi Mar 8 Dec 22

Frequently asked questions

When is the last frost in Clayton?

On average, the last spring frost (32°F) in Clayton is around March 8. In about 1 year in 10 it comes after April 15, and in 9 years in 10 it comes after January 12.

When is the first frost in Clayton?

The first fall frost (32°F) usually arrives around December 22. There’s a 10% chance of a freeze by November 23 and a 90% chance by February 11.

Can it frost in Clayton 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 April 19.

What growing zone is Clayton?

Clayton 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 94521. See growing zones in California.

More: all California frost dates · California growing zones · frost vs. freeze