Frost dates for Fairfield, California
Fairfield doesn't get a freezing night every winter: about 88 years in 100 have one. In those years, half have had their last frost by January 15 and half their first by December 14.
Frost dates for
Fairfield, California
Last spring frost
January 15
Not every winter has one: about 88 years in 100 have a freezing night here. In those years, half have their last frost by this date, and 1 in 10 still have one after February 16.
First fall frost
December 14
In years with a freeze, half have their first one by this date, and 1 in 10 by November 29.
Growing season
336 days
Frost-free days in a typical year. 9 years in 10 get at least 296.
Hardiness zone
9b
2023 USDA map: the coldest night of winter averages 25°F to 30°F. It was 9b on the 2012 map too. All 3 ZIP codes within about 6 miles of the city's center are in zone 9b.
Stations near you disagree. NOAA's Fairfield (2 miles away, at 40 feet above sea level), the one we used, gives a typical last frost of January 15 and a typical first frost of December 14. NOAA's Vacaville Nut Tree Airport (9 miles away, at 110 feet above sea level) gives a typical last frost of February 18 and a typical first frost of November 28. So the typical last frost could fall anywhere from January 15 to February 18 and the typical first frost from November 28 to December 14, depending on whether your garden is more like one or the other. Local terrain matters: hillsides, valley floors, water and city heat can change frost dates a lot over a few miles. Treat the dates here as a starting point, and compare with a nearby gardener or your county extension office.
Print a year planner for Fairfield
Frost risk through the year
How sure are these dates?
A frost date is a probability, not a promise. NOAA worked out, from 30 years of nightly lows, how often the last spring frost and the first fall frost fall on each date. The middle column is the typical year. The outer columns are the early and late years that come about once a decade.
| Early year 1 in 10 | Typical year 1 in 2 | Late year 1 in 10 | |
|---|---|---|---|
| Last frost in spring | December 22 | January 15 | February 16 |
| First frost in fall | November 29 | December 14 | January 9 |
The frost-free season between them runs 336 days in a typical year. In 1 year in 10 there is no freeze at all, and in 1 year in 10 it is 296 days or shorter.
- Hard freeze (28°F): about 44 years in 100 have one. In those years the last typically comes on December 31 and the first on December 24. It is a harder freeze than the 32°F frost line, cold enough to damage many garden plants; how hardy a crop is decides whether it comes through. (The National Weather Service's own hard-freeze threshold varies from office to office.)
- Frost possible (36°F at the station): typically last on February 25 and first on December 1. On clear, still nights the ground can be several degrees colder than the thermometer, so frost can form on plants when the official reading is in the mid-30s.
Planting calendar for Fairfield
These dates count from the typical last and first frosts, using the planting rules published by Colorado State University Extension (spring), Virginia Cooperative Extension (fall crops) and University of Minnesota Extension (garlic, where winters are hard). Weather in any one year can run early or late, so check the forecast before you plant tender crops.
Frost doesn't come every year here: about 88 years in 100 have at least one freezing night. The calendar is built on the dates for the years that do.
We don't give a garlic date here. The rule we use, from the University of Minnesota Extension, counts from the first killing frost, and it works where a hard freeze comes every year before the ground freezes. Your county's extension office can tell you when to plant garlic in your climate.
Your typical last frost comes before mid-February. Where winters are this mild, summer heat limits the garden as much as frost does, and most planting happens in fall and late winter. Your county's extension office publishes a calendar made for your climate.
| When | What to do | Why then |
|---|---|---|
| January | ||
| January 1 to 15 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| January 1 to 15 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
| January 15 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| January 29 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| January 29 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| July | ||
| July 19 to August 2 | Cabbage for fall Start seeds | set the plants out by September 6 |
| August | ||
| August 8 to 22 | Broccoli for fall Start seeds | set the plants out by September 26 |
| September | ||
| September 17 | Snap beans for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| September 21 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| September 22 | Cucumbers for fall Last date to sow | 55 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| September 26 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| September 27 | Summer squash for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| October | ||
| October 1 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| October 11 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| October 21 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| October 30 to November 27 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
| October 31 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| November | ||
| November 13 to December 11 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
| November 27 to December 18 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| November 29 | Tomatoes, peppers, squash, melons, cucumbers Watch the forecast from | in 1 fall in 10 the first frost comes by this date; pick tender crops before a frost |
| December | ||
| December 4 to 18 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| December 11 to 25 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| December 18 to January 1 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| December 18 to January 1 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
Want more insurance? Shift every spring date 32 days later. That plans around February 16, the date after which only 1 spring in 10 has a frost.
For spring bulbs such as tulips and daffodils, plant once the soil has cooled to about 50 to 55°F and keep going until a couple of weeks before the ground freezes. Our guide to fall planting explains how to tell.
Where these numbers come from
These dates come from NOAA's weather station Fairfield (station USC00042934), 2 miles from the center of Fairfield. It sits at about the same elevation, 40 feet above sea level. NOAA rates this station's record as standard: at least 24 of the 30 years, with gaps filled from nearby stations.
Our ZIP code lookup matches these 4 ZIP codes to the same station, so they get the same dates: 94533, 94534, 94535, 94585. Hardiness zones are worked out separately for each ZIP code.
Nearby places
- Vallejo, California: last frost around March 5, first frost around November 21 (15 miles away)
- Concord, California: frost not every year (20 miles away)
- Antioch, California: frost not every year (25 miles away)
See frost dates across California, or look up your own ZIP code for the station nearest you. Want the background? Read what a last frost date really means.