USDA Hardiness Zone 10b
Frost Dates for 92120 — San Diego, California
NOAA 1991–2020 normals from San Diego Montgomery Field, CA (417 ft), 4 miles west.
Updated
Frost is not a yearly event in San Diego: a night at or below 32°F came in 6% of the winters of 1991–2020 at San Diego Montgomery Field, CA, and a 36°F night, cold enough for frost on exposed leaves, in 64%. There is no reliable "last frost date" here; most years have none.
- Winters with a freeze
- 6%
- Winters with 36°F
- 64%
- Coldest month low
- 45°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 18 observed
NOAA normal
Frost risk by date in San Diego
At San Diego Montgomery Field, CA, 4 miles west of San Diego, 6% 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 (64% of winters) and, when they come, fall between about December 25 and January 8. December 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°F64% of yrs | Dec 13 | Dec 24 | Dec 30 | Jan 3 | Jan 8 | Jan 15 | Jan 24 | Feb 1 | Feb 14 |
| 32°F6% 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°F64% of yrs | Dec 1 | Dec 9 | Dec 15 | Dec 20 | Dec 25 | Dec 30 | Jan 5 | Jan 15 | Jan 30 |
| 32°F6% of yrs | too rare for a date | ||||||||
| 28°F0% of yrs | never in 1991–2020 | ||||||||
Freeze probabilities 1991–2020 at San Diego Montgomery Field, 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 92120 →Compare San Diego with another place →
Weather by month in San Diego
August is the warmest month at San Diego Montgomery Field, CA, averaging 82°F by day and 65°F at night; December is the coldest at 67°F and 45°F. Every month stays under a 10% chance of a 32°F night; December is the likeliest at 3%.
Warmth for growing adds up to 5,185 growing degree days a year (base 50°F), more than at 70% of the 283 California stations. 39% of them (2,006) have built up by the end of June, and August adds the most, 733. Precipitation totals 11.1 inches a year, most in February (2.7") and least in August (0.0"); May to September bring 6% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 67 | 46 | 2.3 | 2% | <1 | 211 |
| Feb | 67 | 47 | 2.7 | 1% | 0 | 201 |
| Mar | 69 | 50 | 1.6 | 0% | 0 | 281 |
| Apr | 71 | 52 | 0.8 | 0% | 0 | 347 |
| May | 72 | 57 | 0.3 | 0% | 0 | 445 |
| Jun | 75 | 60 | 0.1 | 0% | 0 | 521 |
| Jul | 80 | 64 | 0.1 | 0% | 0 | 679 |
| Aug | 82 | 65 | 0.0 | 0% | 0 | 733 |
| Sep | 81 | 64 | 0.2 | 0% | 0 | 675 |
| Oct | 78 | 58 | 0.5 | 0% | 0 | 552 |
| Nov | 73 | 50 | 0.9 | 0% | 0 | 342 |
| Dec | 67 | 45 | 1.6 | 3% | 0 | 199 |
Monthly normals 1991–2020 at San Diego Montgomery Field, CA (417 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 Miramar NAS, CA, 6 miles northwest of San Diego, has a 32°F night in 4% of winters against 6% here, and a coolest-month low 1°F warmer (46°F).
When it snows in San Diego, California
Measurable snow is rare here: only 0 of 18 winters from 1991 to 2020 recorded 0.1 inch or more at El Cajon, CA, 8.4 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 92120 is 4 miles from San Diego Montgomery Field, CA, which stands at 417 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 7 other ZIP codes share the station; its figures are presented in full for 92115 (San Diego). The 2023 USDA Plant Hardiness Zone Map lists ZIP 92120 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.