Bring warm clothes with you. San Francisco is located on the water, and even on the hottest summer day, the fog can roll in quickly. When that happens, the wind comes up, and the temperature can plummet as much as 20 degrees in a short time.
There's a famous quote that's attributed, mistakenly, to Mark Twain: "The coldest winter I ever spent was a summer in San Francisco." Regardless of who said or didn't say it, it's true. I would never go to The City wearing shorts, or without a jacket.
When we exchanged homes with a Dutch family, we warned them about this, but they couldn't believe it was true. They later reported that by midafternoon on their first jaunt to SF, the fog came in and sent them running for the car. :)
Clothing/Shoes/Weather Gear: You will always want to have a jacket with you in this town. Even in summer when it is 95 degrees in Oakland it can in the 70s in the city. And although 70s is not normally jacket weather it is when 20 minutes ago you were in the 90s.
Even in Summer, the temperature can be cold in SF. 5 to 10 degrees under the temperature observed elsewhere in the Bay.
So bring sweater and warm clothes to protect you against the wind.
Toiletries and Medical Supplies: The temperature can make you forget the sun. So bring sun cream.
Miscellaneous: Difficult dry the laundry at the hotel.
Clothing/Shoes/Weather Gear: Like I said, you should be prepared for cold weather in San Francisco at all times of the year. It doesn't matter if it is summer, spring, fall, or winter. It can get cold all the time here...and very windy too. Bring a jacket, sweater, or sweatshirts, and maybe some nice thick socks too just in case it is really cold. Hats are always good too of course.
Clothing/Shoes/Weather Gear: Bring Very Comfortable Shoes- As Is the City is extremely Hilly if you walk or even waiting for the Cable car will be awhile. ALWAYS bring a Jacket or Sweatshirt. No Matter how hot it is during the day, the temperature will drop significantly at night- Don't be caught freezing!
Clothing/Shoes/Weather Gear: Whether Mark Twain actually described San Francisco as such is open to debate, however, the statement has some truth to it - especially if you're from warmer climates. You will need a jacket in July and you will probably be more comfortable in pants or jeans than in shorts. It does get quite chilly, especially if you're near the waterfront. If you forget a light jacket or sweatshirt, don't despair; there are plenty of tourist shops that will only be too happy to sell you a jacket with the Golden Gate Bridge embroidered on it.
warm clothes and teeshirts for when it gets warm in the middle of the day. Dont forget your coat or jacket (YOu need it in september)
Miscellaneous: As always there are plenty of shops so if you forget things its not a problem
Luggage and bags:
Nothing special to mention here
Clothing/Shoes/Weather Gear: Comfortble walking shoes as the city is very safe and its most convenient to walk aroud most parts of the city.
If you are going to be close to the bay or ocean area, most definitly bring a sweater or jacket. However if you are a cold blooded dude like me, you don't need outer clothing.
However even I felt cold due to the breeze after the sun set over the Golden Gate bridge and the breeze picked up on the high view points around the bridge.
Don't forget to bring a jacket regardless of the time of year you are there. San Francisco's weather can change quickly with temperatures in the summer dipping into the low 50's with windy conditions. On the other hand, you may see it uncharacteristically warm in the upper 80's. Bring clothes that you can layer. If you visit outside the city, the temerapures can rise quite drastically at times.
Take comfortable shoes to walk in. Driving in the city except by cab is not necessary!
Also bring a small umbrella or slicker in case of rain.
Dress in the city is casual unless you visit one of the upper end restaurants. There you might need a coat and/or tie.
Toiletries and Medical Supplies: Band-aids in case you develop a blister when walking.
Clothing/Shoes/Weather Gear: Dresss in layers and always bring a jacket and more sweaters than you think you need. In the afternoons and evenings it starts to get cold. The Golden Gate bridge can be freezing with it's windy conditions even on a lovely day. Fishermans' wharf can also be cold due being right on the water.
Clothing/Shoes/Weather Gear: Before I moved to San Francisco I read in a few travel guides that the city can be foggy and cold in the summer (especially in August). Somehow I failed to understand that statement to its full extent. I've always thought of California as "sunny California" (a thought which I feel was always in my mind since I don't remember where and how I picked it up). Consequently I didn't bring a sweater (why do it, since I was coming to sunny California?). Next day almost frozen I went out and I bought one. In conclusion if you plan to visit San Franscisco in the summer bring a sweater. Even when it's sunny outside some places in SF can be quite windy, so it's better to be prepared.
Luggage and bags:
A backpack or fannypack is best to get through the sightseeing and with all the walking.
Clothing/Shoes/Weather Gear: Take a lightweight sweatshirt or long sleeved shirt to tie around your waist, cause in the day it may start out kind of warm and breezy but by evening it will be cool and breezy. We had to buy a cheap sweatshirt to wear over to Alcatraz cause we were very cold even dressed in pants and long-sleeved shirts.
Clothing/Shoes/Weather Gear: Bring a jacket, sweatshirt, coat, something warm regardless of the time of year. The tourist trap trinket shops make a killing on people who think, 'Hey! we're going to California in the summer. Why should I bring a jacket?' If you want a wearable reminder of your trip, there are some nice ones interspersed with the garbage. Remember you're going to be surrounded by water (cold water at that) with a nearly constant wind from the ocean. It's a worn-out quote, but it is worth repeating 'The coldest winter I ever spent was one summer in San Francisco.' -- Mark Twain
Clothing/Shoes/Weather Gear: San Francisco is much cooler than the rest of the United States during the summer. Many Americans travel in shorts and t-shirts and nearly get frostbite when they arrive in San Francisco in July! Always bring a sweater or jacket to San Francisco during the summer. This is a photo of the Bay Bridge. Only cars, not pedestrians, are allowed on the bridge, unlike the Golden Gate Bridge.
Clothing/Shoes/Weather Gear: Mark Twain did not REALLY say 'The coldest winter I ever spent was a summer in San Francisco,' but it's true that summers in the city can be damp, foggy, and cold -- especially on the ocean side. Some friends of mine lived on 25th Ave. for years, and one summer they didn't see the sun for 3 months (this is not an exaggeration!). No matter how hot it is elsewhere in the Bay Area, I can almost guarantee that it will be much colder in San Francisco: if you're wearing shorts and a tank top in San Jose, put on jeans and a long-sleeved shirt if you head up the Peninsula; wear socks with your sandals; and take a jacket or sweater with you. Winters are mild (that lovely Pacific current), but can be extremely wet: carry an umbrella and wear puddle-proof shoes. On the other hand, spring and fall can be absolutely gorgeous, temperate and sunny.