San Francisco, California climate: Normal weather by month, frost dates and records
San Francisco's normal year runs from 47°F January nights to 70°F September afternoons, with 22.9 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 14.3°C, January lows of 8°C, September highs of 21°C, 581 mm of precipitation a year.
- NOAA stationSan Francisco Downtown
- Station IDUSW00023272
- Location37.77°N 122.43°W
- Elevation150 ft (46 m)
- Population827,526
On October 22, the normal high in San Francisco is 69°F and the normal low 54°F, and the chance of measurable rain or snow is 14%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for San Francisco.
- Jan 58° 47°
- Feb 60° 48°
- Mar 62° 49°
- Apr 63° 50°
- May 64° 51°
- Jun 67° 53°
- Jul 66° 54°
- Aug 68° 56°
- Sep 70° 56°
- Oct 70° 54°
- Nov 64° 51°
- Dec 58° 47°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in San Francisco each month?
September is the warmest month, with normal highs of 70°F; January the coldest, with normal lows of 47°F. The most precipitation falls in December (4.76 in), the least in July (0.01 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 58°F | 47°F | 52.2°F | 4.40 | 11 | <1 | <1 | 9 h 50 min |
| February | 60°F | 48°F | 54.2°F | 4.37 | 11 | <1 | <1 | 10 h 50 min |
| March | 62°F | 49°F | 55.5°F | 3.15 | 11 | <1 | <1 | 11 h 50 min |
| April | 63°F | 50°F | 56.4°F | 1.60 | 7 | <1 | <1 | 13 h 10 min |
| May | 64°F | 51°F | 57.8°F | 0.70 | 4 | <1 | <1 | 14 h 10 min |
| June | 67°F | 53°F | 59.7°F | 0.20 | 2 | <1 | <1 | 14 h 50 min |
| July | 66°F | 54°F | 60.3°F | 0.01 | 1 | <1 | <1 | 14 h 30 min |
| August | 68°F | 56°F | 61.7°F | 0.06 | 1 | <1 | <1 | 13 h 40 min |
| September | 70°F | 56°F | 62.9°F | 0.10 | 1 | 1 | <1 | 12 h 30 min |
| October | 70°F | 54°F | 62.1°F | 0.94 | 4 | 1 | <1 | 11 h 20 min |
| November | 64°F | 51°F | 57.2°F | 2.60 | 8 | <1 | <1 | 10 h 10 min |
| December | 58°F | 47°F | 52.5°F | 4.76 | 12 | <1 | <1 | 9 h 30 min |
| Year (annual) | 64°F | 51°F | 57.7°F | 22.89 | 71 | 3 | <1 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 14°C | 8°C | 11.2°C | 112 mm |
| February | 16°C | 9°C | 12.3°C | 111 mm |
| March | 17°C | 9°C | 13.1°C | 80 mm |
| April | 17°C | 10°C | 13.6°C | 41 mm |
| May | 18°C | 11°C | 14.3°C | 18 mm |
| June | 19°C | 12°C | 15.4°C | 5 mm |
| July | 19°C | 12°C | 15.7°C | 0 mm |
| August | 20°C | 13°C | 16.5°C | 2 mm |
| September | 21°C | 13°C | 17.2°C | 3 mm |
| October | 21°C | 12°C | 16.7°C | 24 mm |
| November | 18°C | 10°C | 14.0°C | 66 mm |
| December | 14°C | 8°C | 11.4°C | 121 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00023272; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit San Francisco?
Normal highs sit between 65°F and 85°F in June, July, August, September and October. Of those, July has the fewest days with rain (1).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00023272.
What hardiness zone is each San Francisco ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. San Francisco's 26 ZIP code areas run from zone 10a to 10b: 1 in 10a and 25 in 10b. Each ZIP's frost dates are in the frost tool.
| ZIP code | Zone | Land in San Francisco |
|---|---|---|
| 94102 | 10b | 1.7 km² |
| 94103 | 10b | 3.6 km² |
| 94105 | 10b | 1.3 km² |
| 94107 | 10b | 4.8 km² |
| 94108 | 10b | 0.7 km² |
| 94109 | 10b | 2.8 km² |
| 94110 | 10b | 6.2 km² |
| 94111 | 10b | 0.9 km² |
| 94112 | 10b | 8.6 km² |
| 94114 | 10b | 3.6 km² |
| 94115 | 10b | 2.9 km² |
| 94116 | 10b | 6.5 km² |
| 94117 | 10b | 3.3 km² |
| 94118 | 10b | 5.2 km² |
| 94121 | 10b | 6.6 km² |
| 94122 | 10b | 8.4 km² |
| 94123 | 10b | 2.8 km² |
| 94124 | 10b | 12.4 km² |
| 94127 | 10a | 4.8 km² |
| 94129 | 10b | 6.1 km² |
| 94130 | 10b | 2.3 km² |
| 94131 | 10b | 5.2 km² |
| 94132 | 10b | 8.1 km² |
| 94133 | 10b | 1.7 km² |
| 94134 | 10b | 6.6 km² |
| 94158 | 10b | 1.6 km² |
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in San Francisco?
In a normal year in San Francisco, 3 days a year reach 90°F, nights almost never fall to freezing and 71 days bring measurable precipitation.
- Days at 90°F or more
- 3a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- fewer than 1a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 71a normal year
The highest temperature in this station's record (since 1874) is 106°F, on September 1, 2017; the lowest is 27°F, on December 11, 1932.
The wettest calendar year on that record is 1983, with 43.75 in.
Source: NOAA NCEI 1991-2020 annual normals, station USW00023272; records: ACIS (NOAA Regional Climate Centers), station USW00023272. Records use complete months only; a month missing more than three days is left out.
How sunny is San Francisco?
Over a year 80% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around San Francisco, 4.7 kWh per square metre a day. June is the sunniest month (84%) and December the cloudiest (74%). Among the 459 U.S. places of 50,000 or more, that ranks tied 125th (with 50 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 76% | 2.5 |
| February | 77% | 3.4 |
| March | 79% | 4.6 |
| April | 82% | 6.0 |
| May | 81% | 6.7 |
| June | 84% | 7.3 |
| July | 78% | 6.5 |
| August | 77% | 5.8 |
| September | 82% | 5.1 |
| October | 83% | 4.0 |
| November | 81% | 2.8 |
| December | 74% | 2.1 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does San Francisco need?
A normal year in San Francisco brings 2,781 heating degree days, 48% fewer than the median U.S. place (5,373), and 121 cooling degree days, 87% fewer than the median (908). Three months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,872 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 397 | 0 |
| February | 304 | 0 |
| March | 297 | 2 |
| April | 265 | 5 |
| May | 233 | 8 |
| June | 169 | 12 |
| July | 152 | 7 |
| August | 118 | 16 |
| September | 97 | 34 |
| October | 123 | 33 |
| November | 238 | 4 |
| December | 389 | 0 |
| Year (annual) | 2,781 | 121 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00023272. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has San Francisco been warmer than normal lately?
2022 averaged 57.6°F, 0.1°F below the 1991-2020 normal of 57.7°F. 0 of the 2 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 57.0°F | −0.7°F | 22.70 |
| 2022 | 57.6°F | −0.1°F | 15.85 |
Over 94 complete years from 1921 to 2022, the station's annual mean temperature rose at a fitted 3.3°F per century (+0.18°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00023272; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does San Francisco's climate compare?
San Francisco is warmer than 56 of the other 218 places with their own NOAA record in California, and wetter than 148. Across the 7,247 U.S. stations with normals, its annual mean of 57.7°F is warmer than 68%.
In the Köppen classification computed from these normals, San Francisco is Csb: temperate, dry-summer, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near San Francisco share this climate record?
2 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Sausalito, CA7,075 people · 7 mi NW
- Brisbane, CA4,667 people · 7 mi S
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do San Francisco's other NOAA stations record?
2 more NOAA stations keep 1991-2020 normals in or near San Francisco. This page uses San Francisco Downtown; the others differ by site and elevation, and the linked ones have pages of their own:
| Station | From this station | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| San Francisco Oceanside USC00047767 | 5 mi SW | 8 ft | 56.1°F | 46°F | 62°F | 20.6 | 0 | December 30 |
| San Francisco International Airport USW00023234 | 11 mi S | 8 ft | 58.7°F | 45°F | 73°F | 19.6 | – | December 29 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about San Francisco's climate
What is the coldest month in San Francisco?
January, with a normal high of 58°F and a normal low of 47°F. The warmest is September (70°F by day, 56°F at night).
Does it snow in San Francisco?
Rarely. NOAA publishes no 1991-2020 snowfall normal for San Francisco's NOAA station; San Francisco's own co-op station San Francisco Oceanside records 0 inches of snow in a normal year.
What is the rainiest month in San Francisco?
December, with 4.76 in of precipitation in a normal year; the driest is July with 0.01 in.
What plant hardiness zone is San Francisco in?
The USDA's 2023 map puts San Francisco in zones 10a to 10b across its 26 ZIP code areas (10b in 94124, the largest). By the same method at San Francisco's NOAA station, the coldest night of a typical year reaches 39°F (30 years, 1991-2020): zone 10b.
Nearby and next
- San Francisco in OctoberThis month day by day, its records and recent years
- California climateThe statewide normals and every place in the state
- San Francisco Oceanside, CA5 miles from this station, 56.1°F a year
- Oakland Museum, CA9 miles from this station, 59.6°F a year
- Richmond, CA11 miles from this station, 58.8°F a year
- Berkeley, CA12 miles from this station, 58.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made