Frost dates / California / Vacaville

Frost dates in Vacaville, CA

The station on this page is VACAVILLE NUT TREE AP, CA US (USW00093241), 1.4 miles from the city point. Population in the Census 2024 estimate is 103,994.

Zone 9bUSDA average annual extreme minimum 25°F to 30°F, from ZIP 95687 (3.2 miles from the city point used on this page).

Median last 32°F is February 18. Median first 32°F is November 28. The 50% growing-season length is 283 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Last 32°F in spring

NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.

Probability	Date	How to read it
90%	January 11	Earlier date. A last 32°F on or after this day is common.
50%	February 18	Median.
10%	March 25	Later date. A last 32°F on or after this day is uncommon.

First 32°F in fall

NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.

Probability	Date	How to read it
10%	November 12	Earlier date. A first 32°F on or before this day is uncommon.
50%	November 28	Median.
90%	December 18	Later date. A first 32°F on or before this day is common.

32°F growing-season length

Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.

Probability the season is at least this long	Days
10%	325
50%	283
90%	245

28°F threshold

	10%	50%	90%
Last, on or after	February 17	January 15	December 21
First, on or before	November 24	December 10	January 11
Season at least	365 days	334 days	299 days

36°F threshold

	10%	50%	90%
Last, on or after	April 19	March 28	February 26
First, on or before	November 1	November 13	November 30
Season at least	261 days	230 days	201 days

Station VACAVILLE NUT TREE AP, CA US (USW00093241). Completeness flag R, 17 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 99.6%. Freeze dates are conditional on that threshold occurring. Elevation 33.2 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

Planting calendar for Vacaville · Zone 9b

Check a crop against this station

Vacaville, CA

Zone 9bAverage annual extreme minimum 25°F to 30°F

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

California. Nearest qualified station: VACAVILLE NUT TREE AP, CA US (USW00093241), 1.4 miles. Median last 32°F February 18. Median first 32°F November 28. The 50% growing-season length is 283 days.

Open the ZIP page · Crop guides for California

32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	March 25	February 18	January 11
First 32°F on or before	November 12	November 28	December 18

Column order matches the NCEI file: for the last freeze, 10% is the later date and 90% is the earlier date. How to read the probabilities.

A wall calendar surrounded by vegetables, herbs, seed packets, and watering cans.

Planting calendar

Windows below are from UC ANR, UC Master Gardener Program, Time of planting, retrieved 2026-10-10. North and North Coast = Monterey County north; South Coast = San Luis Obispo County south; Interior Valleys = Sacramento, San Joaquin, and similar valleys; Desert Valleys = Imperial and Coachella Valleys. Source line on the page: California Master Gardener Handbook, Table 13.2, Adapted from Vegetable Gardening Illustrated 1994.

Crop

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