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San Francisco in January: Weather, Average temperature and Climate

Discover the weather for San Francisco in January and if it’s a good time to travel (based on historical data).
Check flight prices to San Francisco on Avionero:
January

Weather in San Francisco in January 2025

OK Weather
Mild
☁️
Cloudy
🌊
Cold water
January could be a good time to visit San Francisco, as the weather is generally fine. The average high temperature is around +14°C, and there are typically 5 sunny days in January. However, expect about 13 rainy days, and total monthly rainfall of approximately 113 mm. The weather is changeable so pack for every eventuality. Search flights in one click on Avionero.
Good to know:
  • January is usually the coldest month of the year in San Francisco;

Average weather

☀️
+14°C
Avg. max. temperature
-1°C
Min.
+24°C
Max.
113 mm
Total precipitation
82%
Avg. humidity
2 m/s
Avg. wind
5 ☀️
Sunny Days
14 ⛅️
Cloudy
13 🌦
Rainy
Our opinion: San Francisco has OK weather in January.

Average temperature in San Francisco in January

Here are the expected maximum, average and minimum temperatures in San Francisco for January based on the historical data.
Last Year
Historical Data

The expected average maximum temperature in January is +15°C with a maximum of +19°C and a minimum of +4°C.

The average maximum temperature goes down 13% by the end of the month, compared with the beginning of the month, from +16°C to +14°C.

Is San Francisco warm or cold in January?

San Francisco is typically mild in January.

Maximum temperatures go up compared to the previous month from +14°C to +14°C. The minimum temperature also goes up from +7°C to +7°C.

Pack a light jacket as it will be warm in the day and cool in the evenings.

January is the coldest month in San Francisco, here is the comparison with other months:

Water temperature in San Francisco in January

Water in San Francisco in January is Cold. It varies from +10°C to +14°C, with an average of +12°C. This is almost similar to the air temperature, which averages +14°C.

In January, water temperatures are average relative to the rest of the year:

The warmest water temperatures in San Francisco are reached in September, when the average sea temperature rises to +14°C. The coldest water temperatures are in June, with an average of +11°C.

Can you swim in San Francisco in January?

We would not recommend swimming in San Francisco in January, the water is very cold (+12°C on average). Consider swimming only if you are an experienced cold-water swimmer with proper gear.
🦭
Cold
Below +16°C
🏄‍♂️
Fresh
16°C - 21°C
🏊
Comfortable
21°C - 25°C
👙
Warm
25°C - 28°C
🔥
Very warm
+28°C and up
You will need a full-body wetsuit, cap, gloves, a warm change of clothes, and a hot drink ready for after your swim.

Climate in San Francisco in January

San Francisco weather looks like this, on average, in January and the surrounding months.
DecemberJanuaryFebruary
Avg. temperature
+14°C+14°C+16°C
Min. temperature
-4°C-1°C-1°C
Max. temperature
+23°C+24°C+24°C
Rainfall
117 mm113 mm108 mm
Wind
2 m/s2 m/s3 m/s
Avg. water temperature
+12°C+12°C+12°C
Humidity
81%82%80%
Air pressure
1018 HPa1018 HPa1017 HPa
Sunny days
655
Cloudy days
121412
Rainy days
121311
Snowy days
000

January weather is still as ok as in December. The temperature levels stay the same in the area of +14°C for average maximum temperature during the day. As January arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 117 mm to 113 mm. Humidity rises from 81% to 82%. The average wind speed doesn’t change much during January, staying around 2 m/s. The days becoming less sunny, going from 6 sunny days in December to 5 in January.

February brings much the same weather, it remains ok.

Wind

Wind speed in San Francisco in January based on historical data.
Last Year
Historical Data

The average wind speed is 1 m/s getting up to 3 m/s which is a light breeze; barely moving the tree leaves.

The average wind speed in San Francisco is gradually increasing during January, going from 1 m/s to 2 m/s over the course of the month.

Rain

Amount of rainfall in mm during January in San Francisco based on historical data.
Last Year
Historical Data
Total precipitation in January is about 314 mm, with a 55% chance of rain on a typical day. The maximum amount of rainfall per day is around 47 mm, which is moderate rain. January is a pretty wet month with over 17 rainy days, so don’t forget to pack an umbrella, raincoat, and a pair of galoshes.
January is one of the rainiest months in San Francisco, here is a comparison with other months, total mm:
San Francisco wettest month is December, where a typical day has a 39% chance of precipitation and 117 mm of rainfall per day. July, on the other hand, is the driest month with a mere 0% chance of precipitation and 0 mm of rainfall per day.

How was the weather last January in San Francisco?

This is the weather in San Francisco in January 2023:
1 January
☀️
+16°C
2 January
☁️
+15°C
3 January
☁️
+12°C
4 January
☁️
+15°C
5 January
🌧️
+15°C
6 January
☁️
+15°C
7 January
☁️
+15°C
8 January
🌧️
+16°C
9 January
☁️
+16°C
10 January
🌧️
+14°C
11 January
🌧️
+13°C
12 January
☁️
+18°C
13 January
☁️
+17°C
14 January
🌧️
+15°C
15 January
🌧️
+13°C
16 January
☁️
+13°C
17 January
☀️
+13°C
18 January
☁️
+13°C
19 January
☁️
+12°C
20 January
☀️
+13°C
21 January
☀️
+13°C
22 January
☁️
+15°C
23 January
☀️
+17°C
24 January
☀️
+17°C
25 January
☀️
+19°C
26 January
☀️
+19°C
27 January
☀️
+17°C
28 January
☀️
+14°C
29 January
☀️
+13°C
30 January
☀️
+13°C
31 January
☀️
+14°C
In January 2023 San Francisco had 13 sunny days, 12 cloudy days, and 6 rainy days. The average maximum temperature was +15°C, with an absolute maximum of +19°C and a minimum of +12°C. The average humidity was 76%, with a maximum of 99% and a minimum of 26%. The average wind speed was 1 m/s, with a maximum of 9 m/s and a minimum of 0 m/s.
Are you planning a trip in January?

Climate Change over Years

This is how San Francisco climate have been changing during last 43 years period.

The climate in San Francisco in January has not changed much over the last 43 years.

The average temperature was the lowest in 1982 (+18°C) and the highest in 2014 (+21°C). The driest year was 2013 with only 127 mm of rainfall, and the wettest year was 1983 with 1162 mm.

FAQ

Frequently asked questions about the weather in San Francisco in January:

Is January a good time to visit San Francisco?

It’s always a good time to visit San Francisco, but the weather is changeable in January, so plan a mix of indoor and outdoor activities and exploring, and pack for every eventuality.

Can you sunbathe in San Francisco in January?

January has mild temperatures in San Francisco. Not ideal for sunbathing, but still good for daytime outdoor activities, but plan for cool evenings. Pack a light jacket and shorts!

Can you swim in San Francisco in January?

Swimming in San Francisco in January is challenging and not recommended for inexperienced swimmers or without proper equipment and preparation.

Is San Francisco rainy in January?

San Francisco is often rainy in January. You may get a bit damp when outside, so pack an umbrella, and maybe even a raincoat.

Is it sunny in San Francisco in January?

Usually, it’s not very sunny in San Francisco in January, often it’s pretty cloudy. Pack for any eventuality; layering can help reduce the number of bulky items needed.

Other cities in USA

Check out the weather for other cities in USA.

Monthly weather in San Francisco

Source of the data

For this page, we’ve looked at the typical weather in San Francisco, based on historical hourly weather data from January 1, 1979, to December 31, 2023.

For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.