May weather forecast
San Francisco, CA

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A beautiful dusk view of the Golden Gate Bridge in San Francisco, California
A beautiful dusk view of the Golden Gate Bridge in San Francisco, California

Weather in May

The mild and sunny days of May in San Francisco offer perfect weather for outdoor activities. This month, compared to April, witnesses an increase in temperature, with May’s lowest temperature hovering around 50.5°F (10.3°C). Pleasant marine breezes sweep through the city, offering respite from the increasing heat. Visiting the beach becomes more popular, as the weather continues its march towards the peak of summer. June promises to maintain this trend, as higher temperatures and dry conditions continue to prevail.

Temperature

May begins with an average high-temperature of a still refreshing 65.7°F (18.7°C), reflecting close similarity to the preceding month. San Francisco sees an average low-temperature of 50.5°F (10.3°C) during May.

Humidity

In San Francisco, California, the average relative humidity in May is 73%.

Rainfall

In San Francisco, in May, during 4 rainfall days, 0.35" (9mm) of precipitation is typically accumulated. Throughout the year, there are 58.6 rainfall days, and 6.46" (164mm) of precipitation is accumulated.

Ocean temperature

April through June, with an average ocean temperature of 53.1°F (11.7°C), are months with the coldest seawater in San Francisco, California.
Note: With the appropriate swimsuit, one can swim in 53.1°F (11.7°C) even if temperatures dip below 50°F (10°C); otherwise, be ready for cold shock and breath issues. A fleeting swim around 55.4°F (13°C) is distressing.

Daylight

In San Francisco, the average length of the day in May is 14h and 14min.
On the first day of the month, sunrise is at 6:12 am and sunset at 8:00 pm. On the last day of May, in San Francisco, sunrise is at 5:49 am and sunset at 8:25 pm PDT.

Sunshine

In San Francisco, the average sunshine in May is 10.6h.

UV index

In San Francisco, California, the average daily maximum UV index in May is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for the average person.
Note: The average daily UV index of 4 in May transforms into the following instructions:
Take care. Persons with lighter skin might suffer burns in less than 30 minutes. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.
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Frequently asked questions

What are the temperatures in San Francisco in May?

The average high-temperature, in May, in San Francisco, is 65.7°F (18.7°C), while the average low-temperature is 50.5°F (10.3°C).

What is the average humidity in May in San Francisco?

In May, the average relative humidity in San Francisco, California, is 73%.

How many days does it rain in May in San Francisco?

In May, the rain falls for 4 days. Throughout May, 0.35" (9mm) of precipitation is accumulated.

What are the months with the coldest ocean in San Francisco?

The months with the coldest seawater are April through June, with an average ocean temperature of 53.1°F (11.7°C).

What is the water temperature in May in San Francisco?

In May, the average ocean temperature in San Francisco, California, is 53.1°F (11.7°C). Swimming in 53.1°F (11.7°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

What is the average length of the day in May in San Francisco?

The average day length in May is 14h and 14min.

When are sunrise and sunset in May in San Francisco?

On the first day of May in San Francisco, sunrise is at 6:12 am and sunset at 8:00 pm. On the last day of the month, sunrise is at 5:49 am and sunset at 8:25 pm PDT.

How long on average sun shines in May in San Francisco?

In San Francisco, California, the average sunshine duration in May is 10.6h.

How high is the UV index in May in San Francisco?

In May, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate health threat from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
San Francisco, CA

Average temperature in May - San Francisco, CA
  • Average high temperature in May: 65.7°F

The warmest month (with the highest average high temperature) is September (73.2°F).
The month with the lowest average high temperature is December (55.8°F).

  • Average low temperature in May: 50.5°F

The month with the highest average low temperature is September (56.7°F).
The coldest months (with the lowest average low temperature) are January and December (45.9°F).

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Average pressure in May
San Francisco, CA

Average pressure in May - San Francisco, CA
  • Average pressure in May: 29.98"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).

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Average wind speed in May
San Francisco, CA

Average wind speed in May - San Francisco, CA
  • Average wind speed in May: 7.6mph

The windiest month (with the highest average wind speed) is May (7.6mph).
The calmest month (with the lowest average wind speed) is November (5.5mph).

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Average humidity in May
San Francisco, CA

Average humidity in May - San Francisco, CA
  • Average humidity in May: 73%

The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is October (67%).

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Average rainfall in May
San Francisco, CA

Average rainfall in May - San Francisco, CA
  • Average rainfall in May: 0.35"

The wettest month (with the highest rainfall) is February (1.38").
The driest months (with the least rainfall) are July, August and September (0.08").

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Average rainfall days in May
San Francisco, CA

Average rainfall days in May - San Francisco, CA
  • Average rainfall days in May: 4 days

The month with the highest number of rainy days is March (9.3 days).
The month with the least rainy days is June (1.9 days).

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Average sea temperature in May
San Francisco, CA

Average sea temperature in May - San Francisco, CA
  • Average sea temperature in May: 53.1°F

The best month for swimming (with the highest average sea temperature) is September (57.3°F).
The coldest months (with the lowest average sea temperature) are April and June (53°F).

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Average daylight in May /
Average sunshine in May
San Francisco, CA

Average daylight in May / Average sunshine in May - San Francisco, CA
  • Average daylight in May: 14h and 1min

The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in May: 10h and 4min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

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Average sunshine days in May
San Francisco, CA

Average sunshine days in May - San Francisco, CA
  • Average sunshine days in May: 24.6 days

The month with the most sunshine days is October (25.8 days).
The month with the least sunshine days is March (20.8 days).

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Average UV index in May
San Francisco, CA

Average UV index in May - San Francisco, CA
  • Average UV index in May: 4

The months with the highest UV index are April, June, July, August and September (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 3).

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Average cloud cover in May
San Francisco, CA

Average cloud cover in May - San Francisco, CA
  • Average cloud cover in May: 26

The month with the most cloud cover is March (Cloud cover 36).
The months with the least cloud cover are July and September (Cloud cover 14).

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Average visibility in May
San Francisco, CA

Average visibility in May - San Francisco, CA
  • Average visibility in May: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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San Francisco, California, USA

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