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San Francisco Weather in September: Tips to Prepare & Pack for Your Stay

Jill on a windy day at the Golden Gate Bridge

ByJill Loeffler  • Updated: May 4, 2025 • Published: February 6, 2017

While the rest of the US is cooling down, the San Francisco weather in September is warming up. It's the warmest and sunniest month and it's one of my favorite times of the year.

Autumn? What's that? If you have a trip planned to SF this month, you are in luck. You get to see the City by the Bay at its best, with warm and sunny days and cool evenings. It's our "secret summer"!

On this page, you will find helpful details on how to prepare, including more information on what to pack for your stay. I've also included some of the best things to do this month, as well as a few tips on how to save money during your visit.

Whale watching cruise with the weather in SeptemberEnjoying the September weather in San Francisco while on a whale watching cruise

A Typical Day in September in SF

The picture above was taken early in the month of September, showing a typical sunny day with clear views of the Golden Gate Bridge.

September days usually start out cool and then warm up to around the mid-60s or lower 70s. The afternoons are nice and sunny.

At dusk, it starts to cool down with nighttime temperatures dipping down into the mid-50s.

Perfect Evenings: Since the days are still long in September (the sun goes down after 7 pm through the end of this month), it's the perfect time of year to do more outdoor activities during the day and then head to a rooftop bar or outdoor restaurant at night to relax.

We get very little, if any, rain this time of year. There is not much fog in September either. This means it will cool down at night because the city is not as insulated, but you won't have the overcast skies that you would during the summer months.

We get wind all year around. It typically isn't too windy this time of year, but it does keep the San Francisco weather in September nice and comfortable.

Here are some averages this time of year.

Average temps and rainfall for September

Average High in September: 71° F / 22° C

Average Low in September: 57° F / 14° C

Average Monthly Rainfall: 0.2 inches

Record High: 101° F / 38° C (9/14/1971)

Record Low: 48° F / 9° C (9/27/1955)

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What to Wear for the San Francisco Weather in September

List of must-have items in your bag for September

The San Francisco weather in September offers you a chance to break out shorts or skirts during the day. I often pair them with a short-sleeve shirt.

I never leave home without a light jacket, as some parts of the city are cooler than others. (See some of my favorites)

For example, if you plan to walk across the Golden Gate Bridge or take a ferry to Alcatraz, you'll want to bundle up more than if you are just walking around town.

At night, I swap out my shorts or my skirt for long pants or jeans. I also switch out my sandals to closed-toe shoes to keep my feet warm. I will also grab a heavier jacket or sweater as it does get cool here at night.

Make sure to bring along several items that you can mix and match with layers. This will allow you to add and remove items as the temperature changes throughout the day.

Dress Code: Most places in San Francisco are casual, so jeans and casual tops are fine. A few higher-end restaurants and dinner cruises require nicer attire, but they usually tell their guests if this is required, since everything else here is so casual.

>> More tips on what to pack for your stay

Thinking About Bringing Beach Wear? While we rarely get the hot temperatures that most consider "beach weather," September is one of the best times to visit San Francisco's scenic beaches. In fact, Labor Day weekend is usually when Ocean Beach and Baker Beach are the most crowded.

5 Fun Things to Do in SF in September

1. Catch a free show at Yerba Buena Gardens: Though the Yerba Buena Gardens Festival runs from May to October, this month is the prime time to catch a free performance of Latin jazz, classical fusion, and other global artists at the family-friendly venue near the SFMOMA in SoMa.

2. Head out on a cruise: The San Francisco weather in September makes it the perfect time to head out on a cruise. Several leave Fisherman's Wharf every day and all of them cruise under the Golden Gate Bridge. Find details on my 5 favorites.

3. Explore Alcatraz Island: This small island is about a mile off the coast of San Francisco. It was home to a military prison which turned into a maximum-security prison. Inmates such as Al Capone and Robert "The Birdman" Stroud called it home for several years. It's a must see. More about visiting and getting tickets here.

4. See the SF Giants in action: The SF Giants baseball team has almost a dozen games at home every September. They take on teams such as the LA Dodgers and Arizona Diamondbacks at Oracle Park. Get their schedule for this year here.

5. Attend a cultural festival: Since the San Francisco weather in September is gorgeous, you will find a wide variety of festivals this month. My top picks include Comedy Day in Golden Gate Park, Chinatown Mid-Autumn Moon Festival, and A Taste of Greece. Discover details for this year's events.

>> Tips to find more of our street art here

>> My recommendations to tour Napa Valley

Getting Around SF in September

With the moderate San Francisco weather in September, you will probably end up doing quite a bit of walking. However, if you need a break, here are a few other ways to easily get around town.

Buses & Cable Cars: Both our buses and cable cars offer you the chance to get from one attraction to the next with ease. They run from early in the morning to late at night. You can either pay as you board or buy a multi-day pass through SF Muni. Learn more about how to get around SF.

Hop-On Hop-Off Bus Tour: Another popular and easy option to get around is to take a hop-on hop-off bus tour. These large open-air buses allow you to see the sights as they drive you from one attraction to the next. They offer more than a dozen stops and run about every 15 minutes. Find out more about my favorite option.

Square Bio Pic Jill Loeffler

Hi, I'm Jill!
Dreaming of a San Francisco vacation? As a proud local, I'm here to share my insider tips and personal experiences to help you make the most of this iconic city!

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San Francisco Weather in September: What to Pack

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