Frost dates for Irvine, California
Irvine doesn't get a freezing night every winter: about 50 years in 100 have one. In those years, half have had their last frost by January 5 and half their first by December 25.
Frost dates for
Irvine, California
Last spring frost
January 5
Not every winter has one: about 50 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 2.
First fall frost
December 25
In years with a freeze, half have their first one by this date, and 1 in 10 by December 3.
Growing season
All year
In a typical year there is no freezing night at all. 9 years in 10 get at least 331 frost-free days in a row.
Hardiness zone
10b
2023 USDA map: the coldest night of winter averages 35°F to 40°F. On the 2012 map it was 10a, half a zone colder. ZIP codes within about 6 miles of the city's center: 4 in 10a and 12 in 10b.
Print a year planner for Irvine
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 14 | January 5 | February 2 |
| First frost in fall | December 3 | December 25 | January 20 |
In a typical year there is no freezing night at all. In 1 year in 10, the longest frost-free stretch is 331 days or shorter.
- Frost possible (36°F at the station): about 98 years in 100 have one. In those years the last typically comes on February 1 and the first on December 13. 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 Irvine
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 50 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 5 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| January 19 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| January 19 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| July | ||
| July 30 to August 13 | Cabbage for fall Start seeds | set the plants out by September 17 |
| August | ||
| August 19 to September 2 | Broccoli for fall Start seeds | set the plants out by October 7 |
| September | ||
| September 28 | 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 |
| October | ||
| October 2 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| October 3 | 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 |
| October 7 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| October 8 | 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 12 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| October 20 to November 17 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
| October 22 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| November | ||
| November 1 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| November 3 to December 1 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
| November 11 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| November 17 to December 8 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| November 24 to December 8 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| December | ||
| December 1 to 15 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| December 3 | 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 8 to 22 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| December 8 to 22 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| December 22 to January 5 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| December 22 to January 5 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
Want more insurance? Shift every spring date 28 days later. That plans around February 2, 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 Tustin Irvine Ranch (station USC00049087), 2 miles from the center of Irvine. It sits at about the same elevation, 240 feet above sea level. NOAA rates this station's record as representative: at least 10 of the 30 years, with the gaps filled from nearby stations.
The same station also gives the frost dates for Laguna Hills.
Our ZIP code lookup matches these 5 ZIP codes to the same station, so they get the same dates: 92602, 92618, 92620, 92653, 92694. Hardiness zones are worked out separately for each ZIP code.
Nearby places
- Riverside, California: frost not every year (30 miles away)
- Menifee, California: frost not every year (35 miles away)
- Fontana, California: frost not every year (35 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.