San Francisco (CA) Temperatures: Monthly Averages and Year-Round Insights
On this page, we’ll explore San Francisco’s temperature statistics in detail, including day and night variations and monthly averages. We’ll also compare the annual temperature to other cities in the United States of America.
Monthly Temperature Averages
The moderate changes in the climate in San Francisco ensures gradual weather shifts through each season. On average, maximum daytime temperatures range from a comfortable 23°C in September to a moderate 14°C in January. Nighttime temperatures can drop, with averages reaching 7°C in January.
The chart below illustrates the average maximum day and minimum night temperatures in San Francisco by month:
The early hours of 4 AM to 6 AM often see the lowest temperatures, while 3 PM marks the peak of the day’s heat as the sun’s impact is strongest. September, the city’s warmest month, boasts 270 hours of sunshine.
The chart below shows the average temperature throughout the year:
January, the city’s coldest month, receives about 70 mm of rainfall spread over roughly 9 days. For more information, please visit our San Francisco Precipitation page.
Annual Temperatures in the United States of America Compared
The map below shows the annual temperature across the United States of America. You can also select the different months in case you are interested in a specific month.
very warm
warm
pleasant
moderate
cold
very cold
San Francisco Temperatures Compared World Wide
San Francisco’s average annual maximum temperature is 19°C. Let’s compare this with some popular tourist destinations:
The city of Rome, Italy, has an average annual temperature of 20°C, known for its sunny summers and comfortable winters.
In contrast, in Oslo, Norway, the average annual temperature is significantly lower at 10°C, with mild summers and cold winters.
Meanwhile, Buenos Aires, Argentina, enjoys a humid subtropical climate with an average annual temperature of 23°C, featuring hot summers and mild winters.
In Brisbane, Australia, the average annual temperature is 26°C, making it warmer than Sydney.
How does the temperature feel?
Humidity is an essential factor in how you experience temperature. When a warm period is accompanied by high humidity, it results in a higher perceived temperature. This is especially true when temperatures exceed 25°C, as it can cause greater discomfort.
In San Francisco, during the coolest month, January, you will experience 80% humidity, which is considered very high. This is accompanied by an average maximum temperature of 14°C. Explore our detailed page on humidity levels for further details.
How are these Temperatures Measured?
Generally, temperature data depicting climate is usually given over a 30-year average in order to reduce short-term fluctuations and reveal better long-term trends in climate conditions.
This temperature data is taken from land-based thermometers, ocean buoys, ships, and satellites. These measurements are transmitted to weather stations and climate centers around the globe where they are processed, averaged, and analyzed in order to monitor the trends and create climate models.
Sea vs. Land Temperatures
The influence of nearby oceans or large water bodies significantly affects local temperatures:
- Ocean Influence: Coastal regions tend to have more stable temperatures, as large bodies of water absorb and release heat slowly. This often results in milder winters and cooler summers compared to inland areas.
- Continental Climates: Landmasses well away from large bodies of water tend to show greater extremes in temperature, having hotter summers and colder winters because of the absence of water as a moderating influence.
For more detailed information about San Francisco’s weather, including monthly rainfall, sunshine hours, and humidity levels, visit our San Francisco climate page.
Current temperature in San Francisco (CA)
5 m/s
partly cloudy and no rain
3 m/s
partly cloudy and no rain
2 m/s
broken clouds and no rain
