San Francisco Temperature by Month

The average annual maximum temperature in San Francisco, Spain is 22°C (72°F), with daytime highs ranging from 16°C (61°F) in January to 29°C (84°F) in August. This page covers monthly averages, day-night differences, and how San Francisco compares to cities worldwide.

The climate in San Francisco is known for significant temperature differences throughout the year. At night, this contrast is just as clear, with lows ranging from 22°C (72°F) in August to 10°C (50°F) in January.

The chart below illustrates the average maximum day and minimum night temperatures in San Francisco by month:

Daily lows are most common between 4 AM and 6 AM. By 3 PM temperatures reach their daily high, driven by peak solar heating. August, the warmest month of the year, receives 317 hours of sunshine.

The chart below shows the average temperature throughout the year:

San Francisco's average annual maximum temperature is 22°C (72°F). To put that in context, here's how it compares to a few well-known destinations:

Lisbon, Portugal averages 21°C (70°F) annually, warm summers, mild winters, and rain mainly in the cooler months.

Reykjavík, Iceland averages 9°C (48°F) a year, mild summers by Icelandic standards, but cold winters and frequent wind.

Osaka, Japan averages 22°C (72°F) annually, with hot humid summers, mild winters, and pleasant spring and autumn seasons.

Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.

Temperature alone doesn't tell the whole story, humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.

In San Francisco, January is the coolest month, with average highs of 16°C (61°F) and humidity around 71%, considered high. In August, the warmest month, temperatures average 29°C (84°F) with 63% humidity, conditions that feel high. For a full picture, see our humidity page.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

For cities and regions with significant elevation, altitude is one of the biggest factors shaping local temperatures. As a rule of thumb, temperatures fall by around 6°C for every 1,000 metres gained, so a city at 2,000 metres will typically be around 12°C cooler than a city at sea level in the same region. Higher ground also tends to see more dramatic day-to-night temperature swings, since thinner air loses heat faster after sunset.

For more on San Francisco's weather, including monthly rainfall, sunshine hours, and humidity, visit our San Francisco climate page.