USDA Hardiness Zone 10b
Frost Dates for 94122 — San Francisco, California
NOAA 1991–2020 normals from San Francisco Oceanside, CA (8 ft), 2 miles southwest.
Updated
Frost is not a yearly event in San Francisco: a night at or below 32°F came in 22% of the winters of 1991–2020 at San Francisco Oceanside, CA, and a 36°F night, cold enough for frost on exposed leaves, in 67%. There is no reliable "last frost date" here; most years have none.
- Winters with a freeze
- 22%
- Winters with 36°F
- 67%
- Coldest month low
- 46°F
- Hardiness zone
- 10b
32°F or below, 1991–2020
frost possible on leaves
average, January
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 20 observed
NOAA normal
Frost risk by date in San Francisco
At San Francisco Oceanside, CA, 2 miles southwest of San Francisco, 22% of the winters of 1991–2020 had at least one night at or below 32°F, 5% reached 28°F. Nights of 36°F, enough for frost on exposed leaves, are more common (67% of winters) and, when they come, fall between about December 26 and January 15. December is the month most likely to bring one: a 10% 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°F67% of yrs | Dec 11 | Dec 25 | Jan 1 | Jan 7 | Jan 15 | Jan 26 | Feb 7 | Feb 28 | Apr 7 |
| 32°F22% of yrs | too rare for a date | ||||||||
| 28°F5% of yrs | too rare for a date | ||||||||
| 24°F1% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F67% of yrs | Nov 28 | Dec 5 | Dec 12 | Dec 21 | Dec 26 | Jan 2 | Jan 11 | Jan 24 | Feb 22 |
| 32°F22% of yrs | too rare for a date | ||||||||
| 28°F5% of yrs | too rare for a date | ||||||||
| 24°F1% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at San Francisco Oceanside, 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 94122 →Compare San Francisco with another place →
Weather by month in San Francisco
September is the warmest month at San Francisco Oceanside, CA, averaging 65°F by day and 55°F at night; January is the coldest at 59°F and 46°F. From January to November the chance of a 32°F night stays under 10% each month.
Warmth for growing adds up to 2,303 growing degree days a year (base 50°F), fewer than at 90% of the 283 California stations. 37% of them (858) have built up by the end of June, and September adds the most, 305. Precipitation totals 20.6 inches a year, most in December (4.2") and least in July (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 | 59 | 46 | 3.9 | 6% | <1 | 91 |
| Feb | 60 | 47 | 4.0 | 3% | <1 | 108 |
| Mar | 61 | 48 | 3.0 | 0% | 0 | 141 |
| Apr | 60 | 49 | 1.4 | 2% | <1 | 145 |
| May | 60 | 51 | 0.6 | 0% | 0 | 169 |
| Jun | 61 | 53 | 0.2 | 0% | 0 | 204 |
| Jul | 62 | 54 | 0.0 | 0% | 0 | 250 |
| Aug | 64 | 55 | 0.1 | 0% | 0 | 296 |
| Sep | 65 | 55 | 0.1 | 0% | 0 | 305 |
| Oct | 66 | 53 | 0.9 | 0% | 0 | 305 |
| Nov | 64 | 50 | 2.2 | 2% | <1 | 197 |
| Dec | 59 | 46 | 4.2 | 10% | 1 | 94 |
Monthly normals 1991–2020 at San Francisco Oceanside, CA (8 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 Francisco Dwtn, CA, 3 miles east of San Francisco, has a 32°F night in 0% of winters against 22% here, and a coolest-month low 1°F warmer (47°F).
When it snows in San Francisco, California
Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at San Francisco Oceanside, CA, 2.4 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 94122 is 2 miles from San Francisco Oceanside, CA, which stands at 8 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 94112 (San Francisco). The 2023 USDA Plant Hardiness Zone Map lists ZIP 94122 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.