Frost dates / California / Brentwood
Frost dates in Brentwood, CA
The station on this page is ANTIOCH PUMPING PLT #3, CA US (USC00040232), 3.8 miles from the city point. Population in the Census 2024 estimate is 66,286.
Zone 9bUSDA average annual extreme minimum 25°F to 30°F, from ZIP 94513 (1.9 miles from the city point used on this page).
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.
Planting calendar for Brentwood · Zone 9b
Check a crop against this station
Brentwood, 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), 3.8 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.
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.
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