San Francisco climate: weather by month, temperature, rainfall (2023)

San Francisco's climate can be described as "Mediterranean with cool summers". In fact, both the winter temperatures and precipitation pattern are reminiscent of a Mediterranean climate, but the summer is unusually cool due to the cold currents that run along the California coast and are able to clear the foggy San Francisco Bay and act as a natural air current. conditioner for the city and its surroundings.
Here are the averagestemperaturesmeasured at the international airport, located south of the city and overlooking the bay.

However, in the area there are different microclimates, which should be taken into account by those who plan to move outside the city itself (for example, you can move to theYosemiteNational Park). Moving further away from the sea, you will generally find a more continental climate, a little colder in winter and much warmer in summer.
Regenit is not abundant, as it reaches about 485 millimeters (19 in) per year, but the period from November to March is quite rainy; in April and October the rains are quite rare, while from June to September they are certainly rare and sporadic.
Here is the average rainfall.

Winter, from December to mid-March it is mild and quite rainy. There are sunny and dry periods, sometimes long. Very cold days are rare: the temperature can approach zero (0 °C or 32 °F) at most at night, and only in colder periods is it around 8/10 °C (46/50 °F) during the day. However, frost may occur east of the city, in the Sacramento Valley, and more rarely north and south of the bay.
Snow is an extremely rare phenomenon. On February 5, 1976, it also snowed in the city, where, however, the temperature remained above zero and only on the hills, as in Twin Peaks, significant snow accumulated (13 cm or 5 inches).
Fog may form in the city from time to time, while this phenomenon is more common in the Sacramento Valley.

Primavera, from mid-March to May, the nights are cool or slightly cool, while the days gradually become milder and sometimes pleasantly warm, albeit with a moderate afternoon breeze that brings the temperature down. The rains are getting rarer.

Summer, from June to September it is cool, usually misty in the morning and sunny in the afternoon, with a cool breeze blowing in from the sea. September, albeit a little, is the hottest month. The most foggy districts (and also the windiest in the afternoon) are the westernmost ones (see Sunset District). Rains are rare, especially in July and August when it practically never rains.
Daytime temperatures from June to September are around 17/19°C (63/66°F) in cities on the Pacific coast (see Half Moon Bay) and in the western districts of San Francisco around 21/23°C (70°C). /73 °F) in the eastern districts, 22/24 °C (72/75 °F) inOaklandand Richmond (across the bay), 25/26°C (77/79°F) in towns on the south coast of the bay (see Palo Alto, Mountain View,Fremont), and up to 28 °C (82 °F) inSan Jose, south of the bay.
But beware: just head east into the Sacramento Valley (seeSacramento,Stockton,modest), to encounter very high temperatures, usually around 33/35 °C (91/95 °F), and sometimes even above 40 °C (104 °F).
On the map below we see the average maximum temperatures for August in the San Francisco area, which shows the large differences that occur there. The city of San Francisco is indicated with a red star.

However, from time to time hot desert air manages to reach the city, so much so that temperatures can reach 35/38 °C (95/100 °F) from May to October. In any case, these periods of heat are very rare (in fact, they may not even occur for a whole year), they are short-lived (only one or two days) and the heat is felt only during the day, while at night it is cooled by the sea breeze. For example, on June 14, 2000, the temperature reached 40.6 °C (105.1 °F), but the previous night's minimum temperature was 13 °C (55.5 °F), and the following night was only 16 °C. (61°F).

Val, in October and November it is mild at first and gradually becomes cooler and rainy. Towards the end of October it usually starts to get a little chilly at night.

The amount ofSunlightin San Francisco it is acceptable in winter, when there are a moderate number of sunny days, but also cloudy periods. Sunny days already predominate in spring, while in summer it is usually sunny in the afternoon, but often fog and mist in the morning. There are about 3,000 hours of sunshine per year.

Due to the cold current, themarSan Francisco is cold all year round. In addition, the water temperature remains fairly stable, ranging from 12 °C (54 °F) between January and June to 14 °C (57 °F) between August and November. Here are the average sea temperatures.

best time

The best time to visit San Francisco issummer, from June to September, as this is the driest and hottest season of the year. However, you have to take into account the cool temperatures, and sometimes even a little chilly, at night and at sunrise, as well as the morning fog, so it's best to bring a jacket and a sweater.
Normally the climate in the months of April, May and October is also good, in fact it is usually mild and sunny, although there is a higher chance of rain; moreover, it can be cold at night, especially in April. Also, the afternoon breeze in spring is quite intense.

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San Francisco - Monthly weather

Based on the period 1991-2020

January, the coldest month of the year, is generally a mild month. The average temperature is 10.7 °C (51 °F), with a minimum of 6.8 °C (44.2 °F) and a maximum of 14.6 °C (58.2 °F).
On the coldest nights of the month, temperatures typically drop to around 2.5°C (36.5°F). However, it dropped to −1 °C (30.2 °F) in January 2001.
On the hottest days of the month, temperatures usually reach around 18.5 °C (65.5 °F). However, it reached 23.3 °C (73.9 °F) in January 2015.
Precipitation reaches 100 millimeters (3.9 in), spread over 12 days.
The day lasts an average of 9 hours and 55 minutes.
There is an average of 6 hours of sunshine per day. So the sun shines 60% of the time.
The average humidity is 79%. So the air is normally humid.
The average wind speed is 11 km/h (7 mph).
The average sea surface temperature is 12.5 °C (54.5 °F). Therefore the sea is too cold for swimming.
Februaryit is generally a mild month. The average temperature is 11.9 °C (53 °F), with a minimum of 7.7 °C (45.9 °F) and a maximum of 16.1 °C (61 °F).
On the coldest nights of the month, temperatures usually drop to around 4°C (39°F). However, it dropped to −0.9 °C (30.4 °F) in February 1998.
On the hottest days of the month, temperatures usually reach around 21 °C (69.5 °F). However, it reached 24.4 °C (75.9 °F) in February 1992.
Precipitation reaches 95 millimeters (3.7 in), spread over 11 days.
The day lasts an average of 10 hours and 50 minutes.
There is an average of 7.5 hours of sunlight per day. So the sun shines 68% of the time.
The average humidity is 76%. So the air is normally humid.
The average wind speed is 14 km/h (8 mph).
The average sea temperature is 12 °C (54 °F). Therefore the sea is too cold for swimming.
Marchit is generally a mild month. The average temperature is 13.1 °C (56 °F), with a minimum of 8.5 °C (47.3 °F) and a maximum of 17.7 °C (63.8 °F).
On the coldest nights, which usually fall at the beginning of the month, the temperature usually drops to about 5 °C (41 °F). However, it dropped to −0.3 °C (31.5 °F) in March 1998.
On the hottest days, which usually occur towards the end of the month, the temperature is usually around 23.5 °C (74.5 °F). However, it reached 28.3 °C (82.9 °F) in March 2005.
Precipitation reaches 65 millimeters (2.6 in), spread over 11 days.
The average day lasts 12 hours and 0 minutes.
There is an average of 8.5 hours of sunlight per day. So the sun shines 72% of the time.
The average humidity is 74%. So the air is normally humid.
The average wind speed is 16 km/h (10 mph).
The average sea temperature is 12 °C (54 °F). Therefore the sea is too cold for swimming.
aprilit is generally a mild month. The average temperature is 14.2 °C (58 °F), with a minimum of 9.4 °C (48.9 °F) and a maximum of 19 °C (66.2 °F).
On the coldest nights, which usually fall at the beginning of the month, temperatures usually drop to about 6.5 °C (43.5 °F). However, it dropped to 3.9 °C (39 °F) in April 1999.
On the hottest days, which usually fall towards the end of the month, the temperature is usually around 27 °C (80.5 °F). However, it reached 33 °C (91.4 °F) in April 2009.
Precipitation is 40 millimeters (1.6 in), spread over 7 days.
The average day lasts 13 hours and 10 minutes.
There is an average of 10.5 hours of sunlight per day. So the sun shines 78% of the time.
The average humidity is 70%. So the air is normally humid.
The average wind speed is 20 km/h (13 mph).
The average sea temperature is 12 °C (53 °F). Therefore the sea is too cold for swimming.
It could beit is generally a very mild month. The average temperature is 15.7 °C (60 °F), with a minimum of 10.9 °C (51.7 °F) and a maximum of 20.5 °C (68.9 °F).
On the coldest nights, which usually fall at the beginning of the month, temperatures usually drop to around 9°C (48°F). However, it dropped to 6.7 °C (44.1 °F) in May 2008.
On the hottest days, which usually occur towards the end of the month, the temperature is usually around 29.5 °C (84.5 °F). However, it reached 35.6 °C (96.1 °F) in May 2008.
Precipitation is 12 mm (0.5 in), spread over 5 days.
The average day lasts 14 hours and 20 minutes. So the days are long.
There is an average of 10.5 hours of sunlight per day. So the sun shines 73% of the time.
The average humidity is 70%. So the air is normally humid.
The average wind speed is 22 km/h (14 mph).
The average sea temperature is 12 °C (53 °F). Therefore the sea is too cold for swimming.
Juneit is generally a very mild month. The average temperature is 17.2 °C (63 °F), with a minimum of 12 °C (53.6 °F) and a maximum of 22.4 °C (72.3 °F).
On the coldest nights, which usually fall at the beginning of the month, temperatures usually drop to around 10°C (50.5°F). However, it dropped to 8.3 °C (46.9 °F) in June 1991.
On the hottest days, which usually occur towards the end of the month, the temperature is usually around 31.5 °C (89 °F). However, it reached 40.6 °C (105.1 °F) in June 2000.
Precipitation is only 4 mm (0.2 in), spread over 2 days.
The day lasts an average of 14 hours and 40 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There is an average of 10.5 hours of sunlight per day. So the sun shines 71% of the time.
The average humidity is 69%.
The average wind speed is 22 km/h (14 mph).
The average sea temperature is 12 °C (54 °F). Therefore the sea is too cold for swimming.
Julyit is generally a very mild month. The average temperature is 17.9 °C (64 °F), with a minimum of 13 °C (55.3 °F) and a maximum of 22.8 °C (73 °F).
On the coldest nights of the month, temperatures often drop to around 11°C (52°F). However, it dropped to 9 °C (48.2 °F) in July 1998.
On the hottest days of the month, temperatures usually reach around 30°C (86°F). However, it reached 36.7 °C (98.1 °F) in July 2018.
Precipitation is only 0 mm (0 in.), so on average it never rains for the entire month.
The day lasts an average of 14 hours and 30 minutes. So the days are long.
There is an average of 10 hours of sunlight per day. So the sun shines 70% of the time.
The average humidity is 73%. So the air is normally humid.
The average wind speed is 21 km/h (13 mph).
The average sea temperature is 13 °C (55.5 °F). Therefore the sea is too cold for swimming.
augustusit is usually a warm month. The average temperature is 18.4 °C (65 °F), with a minimum of 13.5 °C (56.2 °F) and a maximum of 23.2 °C (73.8 °F).
On the coldest nights of the month, temperatures often drop to around 12°C (53°F). However, it dropped to 10 °C (50 °F) in August 1995.
On the warmest days of the month, temperatures usually reach around 31 °C (87.5 °F). However, it reached 37.8 °C (100 °F) in August 1993.
Precipitation is only 1 mm (0 in), spread over 2 days.
The day lasts an average of 13 hours and 30 minutes.
There is an average of 9.5 hours of sunlight per day. So the sun shines 69% of the time.
The average humidity is 74%. So the air is normally humid.
The average wind speed is 20 km/h (12 mph).
The average sea surface temperature is 14 °C (57 °F). Therefore the sea is too cold for swimming.
september, the warmest month of the year, is generally a hot month. The average temperature is 18.7 °C (66 °F), with a minimum of 13.3 °C (55.9 °F) and a maximum of 24.2 °C (75.5 °F).
On the coldest nights, which usually occur towards the end of the month, temperatures usually drop to around 11°C (52°F). However, it dropped to 9.4 °C (48.9 °F) in September 1993.
On the warmest days, which usually fall at the beginning of the month, the temperature is usually around 32.5 °C (90.5 °F). However, it reached 40 °C (104 °F) in September 2017.
Precipitation is only 2 mm (0.1 in), spread over 2 days.
The average day lasts 12 hours and 25 minutes.
There is an average of 9 hours of sunshine per day. So the sun shines 73% of the time.
The average humidity is 72%. So the air is normally humid.
The average wind speed is 18 km/h (11 mph).
The average sea temperature is 14.5 °C (58 °F). Therefore the sea is too cold for swimming.
Octoberit is generally a very mild month. The average temperature is 17.4 °C (63 °F), with a minimum of 11.9 °C (53.4 °F) and a maximum of 22.8 °C (73.1 °F).
On the coldest nights, which usually occur towards the end of the month, temperatures usually drop to around 9°C (48°F). However, it dropped to 6.1 °C (43 °F) in October 2002.
On the hottest days, which usually fall at the beginning of the month, the temperature is usually around 30.5 °C (87 °F). However, it reached 35 °C (95 °F) in October 2014.
Precipitation is 20 mm (0.8 in), spread over 4 days.
The average day lasts 11 hours and 10 minutes.
There is an average of 8 hours of sunshine per day. So the sun shines 71% of the time.
The average humidity is 69%.
The average wind speed is 15 km/h (9 mph).
The average sea temperature is 14 °C (57.5 °F). Therefore the sea is too cold for swimming.
novemberit is generally a mild month. The average temperature is 13.6 °C (56 °F), with a minimum of 9.1 °C (48.4 °F) and a maximum of 18.1 °C (64.6 °F).
On the coldest nights, which usually occur towards the end of the month, temperatures usually drop to about 5.5 °C (41.5 °F). However, it dropped to 1.7 °C (35.1 °F) in November 1994.
On the hottest days, usually at the beginning of the month, the temperature is usually around 24°C. However, it reached 27.8 °C (82 °F) in November 2018.
Precipitation reaches 50 mm (2 in), spread over 8 days.
The day lasts an average of 10 hours and 5 minutes.
There is an average of 6 hours of sunshine per day. So the sun shines 57% of the time.
The average humidity is 74%. So the air is normally humid.
The average wind speed is 12 km/h (7 mph).
The average sea surface temperature is 13.5 °C (56.5 °F). Therefore the sea is too cold for swimming.
Decemberit is generally a mild month. The average temperature is 10.8 °C (51 °F), with a minimum of 6.9 °C (44.5 °F) and a maximum of 14.7 °C (58.4 °F).
On the coldest nights of the month, temperatures usually drop to around 2.5°C (37°F). However, it dropped to −1.4 °C (29.5 °F) in December 1998.
On the hottest days of the month, temperatures usually reach around 18.5 °C (65.5 °F). However, it reached 22.8 °C (73 °F) in December 2020.
Precipitation reaches 105 millimeters (4.1 in), spread over 11 days.
The day lasts an average of 9 hours and 35 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There is an average of 5 hours of sunshine per day. So the sun shines 54% of the time.
The average humidity is 76%. So the air is normally humid.
The average wind speed is 12 km/h (7 mph).
The average sea temperature is 12.5 °C (55 °F). Therefore the sea is too cold for swimming.