Frost dates / California / Concord
Frost dates in Concord, CA
The station on this page is CONCORD BUCHANAN FLD, CA US (USW00023254), 3.2 miles from the city point. Population in the Census 2024 estimate is 124,016.
Zone 9bUSDA average annual extreme minimum 25°F to 30°F, from ZIP 94519 (1.3 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 16 | Earlier date. A last 32°F on or after this day is common. |
| 50% | January 9 | Median. |
| 10% | February 12 | 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 28 | Earlier date. A first 32°F on or before this day is uncommon. |
| 50% | December 14 | Median. |
| 90% | January 16 | 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% | 313 |
28°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | January 19 | December 30 | December 10 |
| First, on or before | December 5 | December 23 | January 12 |
| Season at least | 365 days | 365 days | 347 days |
36°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | March 13 | February 14 | January 12 |
| First, on or before | November 14 | December 1 | December 26 |
| Season at least | 331 days | 294 days | 258 days |
Station CONCORD BUCHANAN FLD, CA US (USW00023254). 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 79.4%. Freeze dates are conditional on that threshold occurring. Elevation 5.5 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 Concord · Zone 9b
Check a crop against this station
Concord, 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: CONCORD BUCHANAN FLD, CA US (USW00023254), 3.2 miles. Median last 32°F January 9. Median first 32°F December 14. 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 12 | January 9 | December 16 |
| First 32°F on or before | November 28 | December 14 | January 16 |
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.
Date checks use your device’s calendar and appear after the page loads.