San Francisco County weather

Our guide to the weather in San Francisco County during May

19

Average high

5

UV Index

15mm

Monthly rainfall

72%

Humidity

We've looked at the most up-to-date weather data for San Francisco County, covering the last 12 years up to 2024, plus we've asked our team of travel bloggers for their first-hand experiences in order to answer the most frequently asked questions about San Francisco County weather in May.

What's the temperature like in San Francisco County during May?

The temperature reaches around 19℃ during the daytime in May, falling away to 11℃ at night. The UV index will be moderate at this time of year, so not something to worry about for the average person. However, if you're going to be outside for long periods it's worth wearing a broad spectrum SPF 30+ sunscreen and UV-blocking sunglasses. Remember that bright surfaces, such as water and sand increase UV exposure.

Does it rain in San Francisco County during May?

On average, in May you'll see rain on just one day in the month. In other words, you shouldn't see any of the wet stuff. You're not likely to see a thunderstorm during your trip.

Is it windy in San Francisco County during May?

You're unlikely to experience any strong winds. Expect a light breeze that picks up slightly at times in May. With moderate air temperatures, any breeze will feel cool.

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Weather in San Francisco County

Our month-by-month guide to the weather and climate in San Francisco County

14.9

San Francisco County weather in

January
15.8

San Francisco County weather in

February
16.3

San Francisco County weather in

March
17.9

San Francisco County weather in

April
19.2

San Francisco County weather in

May
21.9

San Francisco County weather in

June
23.1

San Francisco County weather in

July
23.5

San Francisco County weather in

August
24.3

San Francisco County weather in

September
22.1

San Francisco County weather in

October
18.0

San Francisco County weather in

November
14.1

San Francisco County weather in

December