Last spring frost
Mar 21
Frost Dates for Loma Mar, CA
First fall frost
Dec 15
Growing season
275 days
Hardiness zone
9b
In an average year around Loma Mar, CA, the last spring frost (32°F) is about Mar 21 and the first fall frost is about Dec 15, giving roughly a 275-day growing season. To be safe most years, wait until Jan 19 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | May 27 | Apr 26 | Mar 25 |
| Freeze (32°F) | Apr 28 | Mar 21 | Jan 19 |
| Hard (28°F) | Mar 30 | Jan 29 | Dec 15 |
| Severe (24°F) | Mar 6 | Jan 1 | Dec 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 27 | May 16 | May 8 | Apr 30 | Apr 26 | Apr 20 | Apr 13 | Apr 5 | Mar 25 |
| 32°F | Apr 28 | Apr 15 | Apr 7 | Mar 30 | Mar 21 | Mar 9 | Feb 27 | Feb 11 | Jan 19 |
| 28°F | Mar 30 | Mar 13 | Feb 28 | Feb 11 | Jan 29 | Jan 18 | Jan 8 | Dec 30 | Dec 15 |
| 24°F | Mar 6 | Jan 22 | Jan 13 | Jan 6 | Jan 1 | Dec 28 | Dec 20 | Dec 12 | Dec 9 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Nov 4 | Nov 25 | Dec 15 |
| Freeze (32°F) | Nov 21 | Dec 15 | Jan 30 |
| Hard (28°F) | Dec 3 | Jan 4 | Mar 9 |
| Severe (24°F) | Dec 6 | Dec 30 | Mar 6 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 4 | Nov 11 | Nov 16 | Nov 21 | Nov 25 | Nov 29 | Dec 3 | Dec 7 | Dec 15 |
| 32°F | Nov 21 | Nov 29 | Dec 5 | Dec 10 | Dec 15 | Dec 22 | Dec 31 | Jan 10 | Jan 30 |
| 28°F | Dec 3 | Dec 11 | Dec 19 | Dec 28 | Jan 4 | Jan 14 | Jan 25 | Feb 14 | Mar 9 |
| 24°F | Dec 6 | Dec 11 | Dec 18 | Dec 24 | Dec 30 | Jan 4 | Jan 12 | Jan 21 | Mar 6 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Skyline Ridge Preserve, Ca, about 5.6 miles away@if(!empty($station['elevation_ft'])), at 2,270 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Loma Mar, CA?
On average, the last spring frost (32°F) around Loma Mar, CA is about Mar 21. In cooler years it can run later, so for a safer bet many gardeners wait until Jan 19.
When is the first frost in the fall?
The first fall frost around Loma Mar, CA typically arrives about Dec 15. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Mar 21 on average, or Jan 19 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 275 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 94021 Planting calendar → California frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026