Getting today's weather or a forecast for the upcoming week is easy, but if you're planning a visit, you want to know about the climate—what it's generally like. The averages may be more helpful than short-term weather forecasts.
If you're planning a San Francisco vacation,go to the San Francisco vacation plannerfor more information.
Fast Climate Facts
- Hottest Month: September (71 degrees F)
- Coldest Months: December and January (58 degrees F)
- Wettest Months: January (over 4 inches of rain)
Some locals claim there's a phenomenon called "earthquake weather," which they say is hot and dry. This myth goes back to ancient Greece. The truth is that earthquakes start miles underground. They aren't affected by temperature and happen in any weather.
Urgent Seasonal Information
Summer in San Francisco is sometimes gloomy, foggy, and chilly. Those warm-looking, sunny beaches you see on film are far south of San Francisco.
San Francisco in Spring
Spring in San Francisco is sunny and mostly rain-free, making it one of the best seasons to visit before the summer fog sets in.
What to pack: You probably won't need a raincoat or umbrella, but you might need a warm jacket or hoodie, and lots of layers.
Average Temperatures and Rainfall by Month
- March: 62 F / 48 F, 3 inches
- April: 63 F / 49 F, 1.3 inches
- May: 65 F / 51 F, 0.25 inches
You can get more detailed information about San Francisco's spring weather in the guide to San Francisco in March, April, and May.
San Francisco in Summer
If there were one word to describe San Francisco in summer, it would be foggy. And chillier in the evening than you might imagine. Fog is wet. It generates a cold, damp wind as it comes in. In fact, the Fourth of July can feel colder than New Year's Eve.
Don't expect to go swimming, either The ocean temperatures are far too cold unless you have an insulated wetsuit.
What to pack: Summer fog in San Francisco is colder than you can imagine. If you're going from May through July, pack all the layers you think you'll need, then pack one more. Or be prepared to make an emergency sweatshirt purchase.
Average humidity isn't all that high compared to other places, but the fog can turn your carefully-smoothed hairstyle into something that looks more like a haystack. If your hair tends to frizz, pack extra products to keep it tamed.
Average Temperatures and Rainfall by Month
- June: 67 F / 53 F, 0.15 inches
- July: 67 F / 54 F, .0.04 inches
- August: 68 F / 55 F, 0.07 inches
You can get more detailed information about San Francisco's summer weather in the guide to San Francisco in June, July, and August
San Francisco in Fall
Like spring, fall in San Francisco is generally sunny and rain-free.
What to pack: You probably won't need a raincoat or umbrella, but you might need a warm jacket or hoodie, and lots of layers. Check the forecast before you pack to be sure your clothing covers the range of expected temperatures.
Average Temperatures and Rainfall by Month
- September: 71 F / 56 F, 0.26 inches
- October: 70 F / 55 F, 1.26 inches
- November: 64 F / 51 F, 3 inches
You can get more detailed information about San Francisco's fall weather in the guide to San Francisco in September, October, and November.
San Francisco in Winter
It can be chilly in San Francisco in the winter (at least by California standards), and it's also the rainy season.
What to pack: You might need an umbrella or raincoat. And pack lots of layers in case things change fast. Winter is a fickle season, and just looking at the averages doesn't tell the whole story because weather patterns vary a lot from year to year. Your best bet to stay dry and warm is to check the forecast just before you go.
Average Temperatures and Rainfall by Month
- December: 58 F / 47 F, 4.2 inches
- January: 58 F / 47 F, 4.1 inches
- February: 61 F / 48 F, 4.2 inches
You can get more detailed information about San Francisco's winter weather in the guide to San Francisco in December, January, and February.
Relevant Natural Phenomena
The average rainfall is particularly deceivinganywhere in California. Rain depends on what happens in the Pacific Ocean. When the ocean experiences El Nino conditions, it can rain a lot. In other years, you'll hardly see a drop all winter. And when it does rain, a whole month's rainfall often comes in just a day or two.
June Gloom is real.If you don't know Pacific coastal weather patterns, this may sound wrong — but it's true. Even though it is one of the driest months and doesn't rain, June is also the month that gets the least sun, with lots of fog that keep things chilly. Some years, foggy, overcast conditions last longer than a month.It can start as early as "May Gray," sometimes lingering into "No Sky July," or even extend to "Fogust."To find out more and what causesJune Gloom, check out this guide.
| Average Monthly Temperature, Rainfall, and Daylight Hours | |||
|---|---|---|---|
| Month | Avg. Temp. | Rainfall | Daylight Hours |
| January | 57 F | 4.1 inches | 10 hours |
| February | 62 F | 3.0 inches | 11 hours |
| March | 62 F | 3.0 inches | 12 hours |
| April | 63 F | 1.3 inches | 13 hours |
| May | 65 F | 0.3 inches | 14 hours |
| June | 68 F | 0.2 inches | 15 hours |
| July | 69 F | 0.0 inches | 15 hours |
| August | 70 F | 0.1 inches | 14 hours |
| September | 73 F | 0.3 inches | 12 hours |
| October | 70 F | 1.3 inches | 11 hours |
| November | 63 F | 3.2 inches | 10 hours |
| December | 57 F | 3.1 inches | 10 hours |
