Climate Comfort Score
67/100
Good
2026 data Public-data reference. official source
San Francisco, CA Climate
Temperature, precipitation, and comfort score from NOAA NCEI 1991-2020 normals →
30-year climate normals from 1 weather station (1991-2020).
San Francisco, California has an average annual temperature of 59°F and a climate comfort score of 67/100 (Good). Annual precipitation totals 19.6". Based on NOAA 30-year normals (1991–2020).
Avg Temperature
59°F (15°C)
Avg High
67°F
Avg Low
51°F
Annual Precip
19.6"
Comfort Score
67/100
Good
Avg Annual Temperature
59°F
30-year mean (NOAA NCEI)
Annual Precipitation
19.6"
Liquid-equivalent total
Comfort score vs national 100-point ceiling (San Francisco) 67.0%
National median (≈55)
PlainClimate composite — temperature mildness, humidity, precipitation, extreme-weather frequency. Good for the San Francisco area.
Warming context for San Francisco
MethodologyHow the U.S. land temperature anomaly tracks against the global mean since 1900. The current NOAA 1991-2020 normal for San Francisco captures average conditions across the spread shown — the most recent decade is warmer than the 30-year mean.
- United States land mean (NOAA NCEI) +0.11 °C/decade
- Global anomaly (NASA GISTEMP) +0.11 °C/decade
- Paris Agreement thresholds 1.5°C / 2.0°C
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 58°F (14°C) | 45°F (7°C) | 51°F (11°C) | 3.9" | 0.0 | 0.0 |
| February | 61°F (16°C) | 46°F (8°C) | 54°F (12°C) | 4.0" | 0.0 | 0.0 |
| March | 63°F (17°C) | 48°F (9°C) | 56°F (13°C) | 2.7" | 0.0 | 0.0 |
| April | 66°F (19°C) | 49°F (10°C) | 57°F (14°C) | 1.4" | 0.0 | 0.1 |
| May | 68°F (20°C) | 52°F (11°C) | 60°F (16°C) | 0.5" | 0.0 | 0.4 |
| June | 72°F (22°C) | 54°F (12°C) | 63°F (17°C) | 0.1" | 0.0 | 0.7 |
| July | 73°F (23°C) | 55°F (13°C) | 64°F (18°C) | 0.0" | 0.0 | 0.3 |
| August | 73°F (23°C) | 56°F (14°C) | 65°F (18°C) | 0.0" | 0.0 | 0.6 |
| September | 75°F (24°C) | 56°F (13°C) | 65°F (19°C) | 0.1" | 0.0 | 1.6 |
| October | 72°F (22°C) | 53°F (12°C) | 63°F (17°C) | 0.8" | 0.0 | 0.5 |
| November | 64°F (18°C) | 49°F (9°C) | 56°F (14°C) | 2.0" | 0.0 | 0.0 |
| December | 58°F (15°C) | 45°F (7°C) | 51°F (11°C) | 4.1" | 0.1 | 0.0 |
Monthly Precipitation
Average monthly rainfall
January 3.9"
10.9 days with precipitation
February 4.0"
10.8 days with precipitation
March 2.7"
10.3 days with precipitation
April 1.4"
6.2 days with precipitation
May 0.5"
3.3 days with precipitation
June 0.1"
1.2 days with precipitation
July 0.0"
0.0 days with precipitation
August 0.0"
0.4 days with precipitation
September 0.1"
0.9 days with precipitation
October 0.8"
3.1 days with precipitation
November 2.0"
7.2 days with precipitation
December 4.1"
11.1 days with precipitation
Frost Dates & Growing Season
First Fall Freeze
December 26
50% probability date
Last Spring Freeze
December 29
50% probability date
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
2,475
Higher = more heating needed
Cooling Degree Days
200
Higher = more cooling needed
Warmest Month
September
Coldest Month
January
Humidity & Wind
Monthly averages from hourly observations
| Month | Humidity | Wind (mph) | Clear Sky % | Overcast % |
|---|---|---|---|---|
| January | 78% | 7.1 | 19% | 28% |
| February | 74% | 9.1 | 16% | 25% |
| March | 71% | 11.3 | 18% | 18% |
| April | 69% | 13.2 | 21% | 15% |
| May | 72% | 13.8 | 18% | 15% |
| June | 72% | 13.1 | 23% | 12% |
| July | 76% | 12.5 | 12% | 17% |
| August | 72% | 11.6 | 26% | 9% |
| September | 69% | 10.0 | 32% | 11% |
| October | 70% | 8.0 | 28% | 15% |
| November | 73% | 7.1 | 24% | 22% |
| December | 77% | 6.9 | 20% | 28% |
Related Data
PlainEnviro
EPA environmental data — pollution, water quality, and environmental health by location
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Carbon emissions data — greenhouse gas reporting and facility-level CO2 data
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PlainAirData
EPA air quality data — AQI readings, pollutant levels, and air quality trends
Climate Guides
Climate Insight: San Francisco, CA
The NOAA 1991–2020 climate normals describe San Francisco, California as a location with an annual average temperature of 59°F, ranging from a mean daily high of 67°F to a mean daily low of 51°F. September is typically the warmest month of the year, while January is the coldest. These thirty-year averages, computed from station USW00023234, smooth out year-to-year variability and give a baseline expectation for typical conditions in any given month.
Precipitation patterns matter as much as temperature for anyone planning to live, garden, or travel here. San Francisco receives roughly 19.6 inches of precipitation each year, predominantly as rainfall. Growing-season length varies with elevation and microclimate, with the last spring freeze near December 29 and the first fall freeze near December 26. For energy use, 2,475 heating degree days and 200 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.
On PlainClimate's composite comfort index, San Francisco scores 67/100 (Good), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. Use the monthly tables above to plan around specific windows — shoulder seasons for mild highs and lows, peak summer for September-driven heat, or deep winter for January-driven cold. All figures here are thirty-year averages: any single year may run warmer, wetter, drier, or cooler than the normal, so treat them as planning guidance rather than forecasts.
Frequently Asked Questions
What is the average temperature in San Francisco, CA? ▼
The average annual temperature in San Francisco, California is 59°F. The warmest month averages 75°F (24°C) and the coldest averages 45°F (7°C).
How much rain does San Francisco get? ▼
San Francisco receives 19.6 inches of precipitation annually. Based on NOAA 30-year climate normals (1991-2020).
What is the comfort score for San Francisco? ▼
San Francisco has a climate comfort score of 67/100 (Good). This score considers temperature mildness, humidity, precipitation, and extreme weather frequency.
When is the growing season in San Francisco? ▼
Growing season data is not available for San Francisco.
How much energy does heating and cooling require in San Francisco? ▼
San Francisco has 2,475 heating degree days and 200 cooling degree days annually. Higher heating degree days indicate greater winter energy demand, while higher cooling degree days indicate greater summer cooling needs.
Where does this San Francisco climate data come from? ▼
All climate data comes from NOAA U.S. Climate Normals v1.0.1, covering the 30-year period from 1991 to 2020. Data is collected from weather station USW00023234. These 30-year averages are the standard reference for typical weather conditions.
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). Station: USW00023234. For informational purposes only.
Read our methodology — how this data is sourced, computed, and verified.
Related
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainClimate Editorial
