Climate Comfort Score
64/100
Good
NOAA 1991–2020 normals 59°F annual avg Public-domain federal data
San Francisco, CA Climate
Explore average temperature, rainfall, and comfort score sourced from NOAA NCEI's 1991–2020 climate normals →
- 59°F
- Avg annual temp
- 64/100
- Comfort score
- 19.6"
- Annual precip
- -3d
- Growing season
30-year climate normals from 1 weather station (1991-2020).
The climate verdict for San Francisco
San Francisco, California averages 59°F a year and scores 64/100 on the comfort index - good, milder than 51% of U.S. cities.
- 59°F
- annual average temperature (NOAA normal)
- 64/100
- comfort score, milder than 51% of U.S. cities
- 19.6"
- yearly precipitation total
- -3 days
- frost-free growing season
Based on NOAA U.S. Climate Normals (1991–2020) - 30-year averages describing the typical year, not a forecast.
Avg Temperature
59°F (15°C)
Avg High
67°F
Avg Low
51°F
Annual Precip
19.6"
Comfort Score
64/100
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) 64.0%
National median (63)
PlainClimate composite, temperature mildness, humidity, precipitation, extreme-weather frequency. Good for the San Francisco area.
How San Francisco compares to every U.S. city
San Francisco's comfort score vs. all U.S. cities
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
64 Top 49% higher than 51% of 6,915 US cities
Each bar is a band; taller bars hold more US cities. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Warming context for San Francisco
MethodologyThe chart below traces how the U.S. land temperature anomaly has moved against the global mean since 1900. For San Francisco, the NOAA 1991-2020 normal captures average conditions across that spread - notably, the most recent decade runs warmer than the 30-year mean itself.
- 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
Growing Season
-3 days
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% |
What San Francisco's climate means for you
San Francisco runs 59°F a year - peaking in September, coldest in January.
- Gardeners get about -3 frost-free days, with the last spring freeze near December 29 - plan the planting calendar around it, not the regional average.
- Energy bills track 2,475 heating and 200 cooling degree days a year, higher means the furnace or AC runs more.
- Comparing places to live? Line this city up against nearby cities and the national rankings. See rankings
These are 30-year NOAA normals (1991–2020) - the typical year, not a forecast for any specific season.
Climate Guides
Climate Insight: San Francisco, CA
An annual average temperature of 59°F, ranging from a mean daily high of 67°F to a mean daily low of 51°F is what the NOAA 1991–2020 climate normals report for San Francisco, California. September is typically the warmest month of the year, while January is the coldest. That baseline comes from station USW00023234 and thirty years of averaging, so it reflects a typical month rather than any one year's swings.
Beyond temperature, San Francisco averages 19.6 inches of precipitation annually, predominantly as rainfall - a real factor for anyone planning to live, garden, or travel here. The frost-free season averages -3 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near December 29 and the first fall freeze near December 26. Turning to 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 64/100 (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 64/100 (Good), milder than 51% of U.S. cities in the PlainClimate database.
When is the growing season in San Francisco? ▼
San Francisco has approximately -3 frost-free days per year, with the last spring freeze around December 29 and the first fall freeze around December 26.
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, a heating-dominated climate. See our <a href="/guides/reading-weather-data/" class="underline hover:text-brand-600">guide to reading weather data</a> for what these figures mean.
Where does this San Francisco climate data come from? ▼
NOAA U.S. Climate Normals v1.0.1 (1991-2020), from weather station USW00023234 near San Francisco.
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
Every figure on PlainClimate is rendered directly from NOAA 1991-2020 U.S. Climate Normals data, no number is typed in by an editor. This page draws directly on NOAA 1991-2020 U.S. Climate Normals data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.