Summer in San Francisco: What to Expect From Fog, Micro-Climates, and Advice From a Local

San Francisco is wonderful to visit any time of year—but summer often surprises first-time visitors. Because the City sits on a peninsula surrounded by the Pacific Ocean and the San Francisco Bay, it has a famously temperate climate that behaves very differently from much of California. In fact, summer in San Francisco can feel colder, foggier, and far more unpredictable than people expect—especially compared to just across the Bay.

If you’re planning a summer visit, it helps to know what you’re getting into. From Karl the Fog and chilly evenings to wildly different neighborhoods experiencing totally different weather at the same time, and even summer events, here’s what to know before you pack your bags, straight from a local.

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Things to Know Before Visiting San Francisco in Summer

1. Karl the Fog
2. Summer is Cold
3. Weather changes through the day
4. Micro-climates
5. No Air Conditioning
6. On a nice day – Everyone is out
7. Summer Events
   • 4th of July Fireworks
   • Pride
   • Neighborhood Festivals
   • Races – SF Marathon, Bay to Breakers and more…
   • Concerts – Outside Lands and Stern Grove
8. Indian Summer

1. Karl the Fog

Perhaps San Francisco’s most famous weather is the fog, which locals have named “Karl”.  He even has his own Instagram.  Locals even refer to summer months by their own nicknames.  You should know this if you chose to visit in “June Gloom,” “No-Sky July,” or “Fogust.” 

San Francisco’s unique climate occurs during the summer because when the temperatures get hot inland, the fog over the Pacific Ocean gets sucked in and sits at the edge, right on top of San Francisco.  On a typical summer day, it will be foggy in the morning and it often “burns off” by the afternoon.  There are often a few warm and sunny days in San Francisco, which are then followed by the fog being sucked into the City.  You can literally watch the fog roll in over the hills and across the Bay. 

While this might sound unpleasant, locals have learned to enjoy it.  It is magical to watch the fog moving inside the Bay.  The sound of fog horns from the Golden Gate Bridge is a sound many locals love.  My favorite place to watch the fog roll in is along the north side of the City, watching the fog crawl along the Bay towards Alcatraz.  It feels like the City is just being dramatic and showing off her incredible beauty. 

2. Summer is Cold

Now that you have been introduced to Karl, you probably know that fog doesn’t exactly mean warm temperatures.  While San Francisco has a reputation for being cold, the average temperature in July is a high of 67° F and a low of 54° F.  Not exactly “winter” to hardier people that are accustomed to more extreme weather. 

However, San Francisco residents are used to their incredibly mild weather and like to complain about how it is “freezing” in July (myself included).  If you are looking to escape the sweltering heat inland during the summer and enjoy some “natural” air conditioning, San Francisco might just be the perfect place for your summer vacation.

3. Weather Changes Throughout the Day

Just because the weather is warm and sunny and you are enjoying a perfect afternoon in Fort Mason, that does not mean that weather will last.  When the sun begins to set and you watch the sunset behind the Golden Gate Bridge, sometimes Karl the fog decides to make an appearance, rolling into the Bay and whipping up the hills. 

If you are caught without a jacket you could be freezing and running home (or into a bar) to warm up.  Two things I always tell people to bring when they visit San Francisco is comfortable walking shoes and a jacket.  I often carry a big purse just so I can carry a light layer if I need it, even if the weather seems perfect when I leave the house. 

4. San Francisco Micro-Climates

Something else San Francisco is famous for is the hills.  This means there are opportunities for stunning views all over the City.  It also means there are micro-climates in different neighborhoods.  The fog could start to roll in and sit at the edge of Twin Peaks or Divisadero, keeping the west side of the City under a blanket of fog, while Noe Valley and the Mission may be warm and sunny.  You can take public transportation to a new neighborhood and encounter an entirely different climate.  Once again, this mean ALWAYS bring a light jacket with you. 

I love walking up to the top of a hill in a sunny neighborhood and seeing different climates around me.  Sometimes you can see that you are standing in sunshine while you see fog in three directions around you.  Once of my favorite places to see this is from the top of Sanchez at 23^rd Street.  This view is part of one of the walking routes on my post about How to Find the Best Views in Noe Valley. 

5. No Air Conditioning

Because of the previously mentioned summer temperatures, most buildings in San Francisco have been designed without air conditioning.  Most of the time, this is completely fine and comfortable.  However, on the rare days that San Francisco decides to have a heat wave, it can be uncomfortably hot inside.  My old Marina apartment got up to 100° F inside once.  It was more comfortable to be outside than inside.

6. On a Nice Day – Everyone is Outside

Now that leads me to how much residents of San Francisco appreciate the rare warm and sunny summer day.  Everyone is out, enjoying the parks and sunshine.  Outdoor dining and parklets are packed, neighborhoods are alive. 

One time my dad was visiting, we walked by Dolores Park on a sunny Saturday afternoon.  The park was so packed with people sitting on blankets, having picnics and enjoying the scenery, my dad asked me what event was happening.  I told him the event was that it was a sunny Saturday afternoon.  He had never seen a park so packed with no official “event” before.  In San Francisco, a sunny summer day is a reason to celebrate.

7. San Francisco Summer Events

This brings me to some summer events to be aware of.  Despite the potential cold and foggy weather, there are a lot of celebrations and events that occur every summer in San Francisco.  Depending on your interests, you may or may not want to visit during these events. 

4th of July

In most of America, Independence Day means sunshine and barbeques.  In San Francisco, many locals leave (or wish they left). Most years, 4^th of July is cold and foggy.  Not exactly the ideal weather for a picnic and fireworks. 

If you are into fireworks, there will be plenty, although the visibility could be questionable.  On foggy evenings, the fireworks explode inside the fog and just look like a cloud that is glowing in the sky.  A little less dramatic than a typical fireworks show. 

However, one neighborhood that goes nuts on the evening of 4^th of July is the Mission.  It blows my mind every year, but people all over the Mission set off fireworks in the street.  I’m not even talking about some little homemade fireworks, many of these look professional.  Locals will gather on top of hills or in Dolores Park to watch.  It is definitely a sight to see, especially if you happen to be visiting on a year where the night is clear.  If you decide to stay in the Mission, be aware there will be fireworks going off constantly, late into the night. 

To see a professional show, Fisherman’s Wharf is the location of the official fireworks show in San Francisco.  On a clear night you can see fireworks in Marin County and Oakland from the City. 

Pride

Pride happens during the last week of June in San Francisco.  It is a weeklong event with many events including a parade.  If you are planning to drive in San Francisco during that time, be aware of when events are happening to avoid closed streets and potential traffic.  Sometimes when there are parades along Market Street it can be extremely difficult to drive across the City. 

If you want to visit for Pride, Dolores Park is packed during this weekend, especially if it is sunny.  There is also a giant pink triangle on Twin Peaks that can be seen from many places in the City.  It is a fun time to be in town and feel the energy of the event.   

Neighborhood Festivals

Many neighborhoods have festivals on weekends throughout the summer.  They are fun to wander, check out work by artists, taste festival food, listen to live music, and hang out in the beer gardens or local bars.  Some of my favorites are the Fillmore Jazz Festival, the North Beach Festival, and the Union Street Festival.

Summer Races – Bay to Breakers, SF Marathon, and More

There are several races in San Francisco throughout the summer.  Bay to Breakers is at the end of May and feels a little more like a parade than a race, but is a fun event as a runner or spectator.  The San Francisco Marathon is usually in July. 

There are several other smaller races that take place throughout the summer.  The reason to be aware of them is they can close streets (or lanes on the Golden Gate Bridge) during the morning hours while the race is happening and can cause delays if you are driving (or trying to call an Uber). 

Summer Concerts – Outside Lands and Stern Grove

Outside Lands is a multi-day concert in Golden Gate Park, and Stern Grove is a series of free concerts that happens in Stern Grove every summer.  Even though Stern Grove is free, you now need to reserve tickets ahead of time online to attend so it is worth looking into before your trip if you are interested in attending. 

8. Indian Summer in San Francisco

The warmest months of the year in San Francisco are actually September and October, which is referred to as Indian Summer.  If you prefer to visit during the months of the most ideal weather in San Francisco, September and October are the best bet.  But like I said, I think San Francisco is wonderful any time of year.  Just make sure to pack a jacket for any time of year in San Francisco. 

Summer in San Francisco

Summer in San Francisco is full of surprises, but once you understand (and embrace) the fog, the micro-climates, and the daily temperature swings, it’s easy to see why locals love it. If you are looking for an escape from the heat, or just want to experience the beauty of watching the fog roll into the Bay and listening to the fog horns, summer can be an amazing time to visit San Francisco.  Pack comfortable walking shoes, bring a light jacket everywhere, and you’ll be perfectly prepared to enjoy the City. No matter the season, San Francisco has a way of winning people over.