When is the last spring frost in Pittsburg, CA?

The median last 32°F date at the station on this page is January 12. NOAA’s 1991–2020 normals give a 50% chance the last spring minimum of 32°F or lower occurs on or after that date. The 90% date is December 20. The 10% date, the later one, is February 1. These are normals, not a forecast for this spring.

What USDA zone is Pittsburg, CA?

The zone on this page is 9b, from ZIP 94565 in the 2023 PRISM table of the USDA Plant Hardiness Zone Map. That ZIP is 1.8 miles from the city point. USDA defines the zone as the average annual extreme minimum, shown here as 25°F to 30°F. It is a winter-cold band, not a frost date and not a forecast.

How far away is the weather station?

The station named on this page is 8.2 miles from the city point in a straight line. Frost dates are 1991–2020 NOAA climate normals for that instrument. They are not a National Weather Service forecast for one night, and they are not the temperature in every yard. The page names the station so the miles stay attached to the dates.

Frost dates in Pittsburg, CA

Direct answer. In Pittsburg, CA, the nearest qualified NOAA station is ANTIOCH PUMPING PLT #3, CA US (USC00040232), 8.2 miles from the city point. The median last 32°F date is January 12, and the median first 32°F date is December 19, from the 1991–2020 U.S. Climate Normals. The 2023 USDA zone is 9b (25°F to 30°F), from ZIP 94565 in the PRISM table, 1.8 miles from the same city point.

Population in the Census 2024 estimate is 77,131. The station is ANTIOCH PUMPING PLT #3, CA US (USC00040232).

Zone 9bUSDA average annual extreme minimum 25°F to 30°F, from ZIP 94565 (1.8 miles from the city point used on this page).

Median last 32°F is January 12. Median first 32°F is December 19. The 50% growing-season length is 343 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%	December 20	Earlier date. A last 32°F on or after this day is common.
50%	January 12	Median.
10%	February 1	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 29	Earlier date. A first 32°F on or before this day is uncommon.
50%	December 19	Median.
90%	January 12	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%	365
50%	343
90%	315

28°F threshold

	10%	50%	90%
Last, on or after	January 22	January 2	December 16
First, on or before	December 9	December 29	January 16
Season at least	365 days	365 days	347 days

36°F threshold

	10%	50%	90%
Last, on or after	March 12	February 8	January 11
First, on or before	November 18	December 4	December 28
Season at least	331 days	299 days	263 days

Station ANTIOCH PUMPING PLT #3, CA US (USC00040232). Completeness flag R, 19 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 81.3%. Freeze dates are conditional on that threshold occurring. Elevation 18.3 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

Questions

When is the last spring frost in Pittsburg, CA?: The median last 32°F date at the station on this page is January 12. NOAA’s 1991–2020 normals give a 50% chance the last spring minimum of 32°F or lower occurs on or after that date. The 90% date is December 20. The 10% date, the later one, is February 1. These are normals, not a forecast for this spring.
What USDA zone is Pittsburg, CA?: The zone on this page is 9b, from ZIP 94565 in the 2023 PRISM table of the USDA Plant Hardiness Zone Map. That ZIP is 1.8 miles from the city point. USDA defines the zone as the average annual extreme minimum, shown here as 25°F to 30°F. It is a winter-cold band, not a frost date and not a forecast.
How far away is the weather station?: The station named on this page is 8.2 miles from the city point in a straight line. Frost dates are 1991–2020 NOAA climate normals for that instrument. They are not a National Weather Service forecast for one night, and they are not the temperature in every yard. The page names the station so the miles stay attached to the dates.

Planting calendar for Pittsburg · Zone 9b

Check a crop against this station

Pittsburg, 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: ANTIOCH PUMPING PLT #3, CA US (USC00040232), 8.2 miles. Median last 32°F January 12. Median first 32°F December 19. The 50% growing-season length is 343 days.

Open the ZIP page · Crop guides for California

32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	February 1	January 12	December 20
First 32°F on or before	November 29	December 19	January 12

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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