San Francisco is a fabulous City but like all City’s the weather can have a big impact on how enjoyable your trip will be. Cold weather and heavy rain can ruin a trip if unprepared. and extreme heat can make city visits quite uncomfortable. So what is the weather like in San Francisco?
Well, fortunately, the Weather is fairly good all year round with fairly limited variation. Read on as we explain the Climate and the Seasons in San Francisco so you can find out what is the best month to visit San Francisco for You.
Climate
San Francisco’s Climate is an interesting one. Its geographical location creates an extremely unpredictable climate. To the west are thousands of miles of uninterrupted ocean and to the east are large hot dry plains. The hills of San Francisco are where these two opposites meet. The hot dry plains suck in cool air from the pacific which can cause the infamous San Francisco fog.
However, despite this variability and unpredictableness, the Climate is actually fairly stable. The variations are all quite mild and the area rarely sees anything very extreme. Mild in the Winter and Warm in the summer.
What this really means to you, is ANY time is a good time to visit San Francisco!
One thing to note about the Climate though is its tendency toward Micro Climate Changes! What the hell is that? Basically small changes in location (and time of day) can have dramatic differences in weather.
Take one day we had in late May. We ate breakfast in North Beach outside in the beautiful morning sun. We walked up Lombard Street to catch the Cable car to Union Square. In the Queue, it began to rain. We shivered our way over to Union Square in icy winds and rain, arriving so cold we had to shelter in a nearby Coffee shop for warmth. After an hour or two we ate lunch on a roof terrace where it was so scorching hot we got sunburnt and could barely touch the table surface due to it being superheated by the sun. Later on, we enjoyed Ice Cream and cold beers while we waited for our bay Cruise, on which my hands became so cold I could no longer operate the camera.
These sorts of variations are not all that uncommon. Layers are the order of the day, you can be freezing cold one minute and red hot the next. Just because you are warm in the morning sun do not assume shorts and a T-shirt are all you will need!
Fog is another big weather issue in San Francisco, but that varies with the seasons so we will address that later.
Average Temperatures
As mentioned San Francisco is susceptible to VERY wild Micro-climates and as such large amounts of Average temperatures are next to meaningless. But Its not a weather page without some data so here we go:
As you can see the Temperatures are fairly stable year-round with only modest increases in summer and never getting too cold in winter.
Spring: March-May
Spring is a very pleasant time to visit. The temperatures while not high are warm enough to enjoy the outdoors, without the need for extensive clothing. Winds tend to be lower and the Infamous fog is infrequent in its appearance until May sets in. Combined with spring flowers starting to bloom and the sense of the approaching summer leads Spring to be a wonderful time to visit the City.
Rain is infrequent from April onwards and it can be relied upon to be dry most days.
Summer: June – August
San Francisco Summers tend to be long and dry. Temperatures don’t often reach very high temperatures meaning activities such as swimming are not popular, however, these milder temperatures mean exploring the City is still very comfortable even in the height of summer.
There is very little Rain fall throughout the season which is good news the bad news is Summer sees the brunt of the Sea Fog that forms from the cooling Pacific winds. This will wane as the season draws on but is always a possibility whatever the month.
Autumn/Fall: September – November
While Autumn/Fall sees the temperatures begin to drop off they don’t fall nearly as fast as they rose in Spring. In fact with the Fog now fading into memory, and the winds lessening. Autumn can feel even warmer than the summer months.
Rain tends to stay away in September and October and begins to return infrequently in November. Autumn tends to be the local’s favorite Season as they enjoy the warm clear days. It’s a great time to be in the City.
Winter: December – February
In Winter the weather does fall apart significantly. Rain is frequent, persistent, and heavy. Not great adjectives to apply to rain. Temperatures are much cooler and the days are significantly shorter.
It is not winter like in a lot of US Cities, there is very little chance of snow and almost no chance of real settled snow. Sub-freezing temperatures are exceedingly rare and when it isn’t raining the days can be clear and very pleasant. But it’s still, not the greatest season to be outside. Plan for more indoor activities. and Enjoy the fantastic food scene.
At least it will far less busy!
San Francisco Fog
Fog is a phenomenon synonymous with san Francisco. In fact, this weather pattern is repeated all along the Pacific Seaboard. There are some complex Scientific reasons for this that we will briefly explain below but first, and more importantly, We will explain what it means for you practically.
From May through to the end of August the Fog will form Most days. Most mornings will begin with part or all of the city covered in a thick dense blanket of fog. As the morning turns to afternoon and the temperature rises the fog will “burn” off leaving a pleasant sunny day. By late afternoon as the temperature begins to drop again the fog will return.
While this pattern is not guaranteed, it is the Normal pattern of a summer day in San Francisco. Abnormal weather patterns can and do disrupt this cycle but you can reasonably expect this pattern most days.
The reasons for the fog are fairly complex but can be summarised quite easily. The thousands of Miles of uninterrupted Pacific ocean create a layer of (invisible) particles above the surface called the Marine Layer. This layer of particles is rather Good at forming Fog. As the temperatures dip, Fog forms in this layer. The Warm Dry air of the Central valley rises upwards and the cooler coastal air rushes in to fill the void. Pulling the sea Fog from the sea in with it. Once over the warmer land the fog then slowly dissipates. and the cycle repeats.
For better or worse it’s a feature of the San Francisco Climate… and at least it can make for some STUNNING Golden Gate Bridge Photos.
Best time to visit San Francisco
We really do think San Francisco can be enjoyed at any time of the year. Of course, if you are free to choose any time of the year to plan your trip, which is not often the case, Then Autumn is really the top Season. It feels every bit as warm and dry as Summer but the lack of Fog really is a boost.
Spring is not far behind but just a bit cooler than autumn. Summer is still fantastic and the Fog, while cool and a bit annoying, does clear most days, leading to beautiful bright sunshine. Winter is the “bust” season but the city can still be enjoyed, just in a different way, it will also be immeasurably quieter in the winter, while in Spring and Fall the crowds build. In summer things can be really hectic and queues and wait times for attractions can be huge, along with sky-high hotel prices.
Have Your Say
Let us know if you have experienced the Infamous San Francisco Fog? or any other weather phenomena while visiting? or maybe you would like to know what the weather might be like on your upcoming trip. Just drop us a comment below and we will get back to you asap.