USDA Hardiness Zone 10b
Frost Dates for 92122 — San Diego, California
NOAA 1991–2020 normals from San Diego Miramar NAS, CA (477 ft), 5 miles east.
Updated
Frost is not a yearly event in San Diego: a night at or below 32°F came in 4% of the winters of 1991–2020 at San Diego Miramar NAS, CA, and a 36°F night, cold enough for frost on exposed leaves, in 52%. There is no reliable "last frost date" here; most years have none.
- Winters with a freeze
- 4%
- Winters with 36°F
- 52%
- Coldest month low
- 46°F
- Hardiness zone
- 10b
32°F or below, 1991–2020
frost possible on leaves
average, December
35 to 40°F (1.7 to 4.4°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 0%
- Snow per year
- 0"
median, 1991–2020
median, 1991–2020
0 of 19 observed
NOAA normal
Frost risk by date in San Diego
At San Diego Miramar NAS, CA, 5 miles east of San Diego, 4% of the winters of 1991–2020 had at least one night at or below 32°F, and none reached 28°F. Nights of 36°F, enough for frost on exposed leaves, are more common (52% of winters) and, when they come, fall between about December 30 and January 7. January is the month most likely to bring one: a 3% chance in a given year. 62 of the 283 other California stations behind this site's ZIP pages freeze in fewer than half of winters too.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F52% of yrs | Dec 15 | Dec 24 | Dec 31 | Jan 4 | Jan 7 | Jan 14 | Jan 25 | Feb 3 | Feb 18 |
| 32°F4% of yrs | too rare for a date | ||||||||
| 28°F0% of yrs | never in 1991–2020 | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F52% of yrs | Dec 7 | Dec 14 | Dec 19 | Dec 24 | Dec 30 | Jan 3 | Jan 8 | Jan 21 | Feb 1 |
| 32°F4% of yrs | too rare for a date | ||||||||
| 28°F0% of yrs | never in 1991–2020 | ||||||||
Freeze probabilities 1991–2020 at San Diego Miramar NAS, CA, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 92122 →Compare San Diego with another place →
Weather by month in San Diego
August is the warmest month at San Diego Miramar NAS, CA, averaging 82°F by day and 65°F at night; December is the coldest at 67°F and 46°F. Every month stays under a 10% chance of a 32°F night; January is the likeliest at 3%.
Warmth for growing adds up to 5,208 growing degree days a year (base 50°F), more than at 71% of the 283 California stations. 39% of them (2,023) have built up by the end of June, and August adds the most, 738. Precipitation totals 11.5 inches a year, most in February (2.7") and least in August (0.0"); May to September bring 5% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 67 | 47 | 2.3 | 3% | <1 | 227 |
| Feb | 67 | 48 | 2.7 | 1% | 0 | 217 |
| Mar | 68 | 50 | 1.6 | 0% | 0 | 271 |
| Apr | 70 | 52 | 0.8 | 0% | 0 | 338 |
| May | 72 | 57 | 0.3 | 0% | 0 | 442 |
| Jun | 75 | 60 | 0.1 | 0% | 0 | 530 |
| Jul | 80 | 64 | 0.1 | 0% | 0 | 684 |
| Aug | 82 | 65 | 0.0 | 0% | 0 | 738 |
| Sep | 82 | 63 | 0.1 | 0% | 0 | 671 |
| Oct | 78 | 58 | 0.6 | 0% | 0 | 544 |
| Nov | 72 | 51 | 0.9 | 0% | 0 | 349 |
| Dec | 67 | 46 | 2.0 | 1% | <1 | 200 |
Monthly normals 1991–2020 at San Diego Miramar NAS, CA (477 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, San Diego Montgomery Field, CA, 5 miles southeast of San Diego, has a 32°F night in 6% of winters against 4% here, and a coolest-month low 1°F colder (45°F).
When it snows in San Diego, California
Measurable snow is rare here: only 0 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at Poway Valley, CA, 15.4 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 92122 is 5 miles from San Diego Miramar NAS, CA, which stands at 477 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 92126 (San Diego). The 2023 USDA Plant Hardiness Zone Map lists ZIP 92122 in zone 10b, the band where the coldest night of the year averaged 35 to 40°F (1.7 to 4.4°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across California →
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.