May weather forecastSan Francisco, CA
May
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.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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).
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).
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).
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%).
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").
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).
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).
Average daylight in May /
Average sunshine in May
San Francisco, CA
- Average daylight in May: 14h and 12min
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 36min
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).
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).
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).
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).
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).
