San Francisco is fortunate to be blessed with a moderate climate... or so it seems!
But make no mistake, this is NOT Los Angeles and it is very unlikely that you'll be comfortable in shorts, esp in the summer when morning fogs are legendary!
As you can see from the pic below, I packed along nothing but shorts and had to rush to the nearest store to buy THICK legstockings! Besides packing your usual clothings, REMEMBER to also bring along the following:
A windbreaker, sweater or trenchcoat which you'd probably use almost daily IN SUMMER! I mean, can you believe it if I were to tell you that this photo was taken in the middle of July (re: My first trip to San Fran in the 1990s).
The folks here are generally pretty well-dressed. If you intend to go to an exclusive restaurant or visit the theaters, do pack along an evening dress or two and a suit (for guys). Don't worry if you forget to bring enough warm clothings. There are TONS of sweatshirt shops in Fisherman's Wharf. You can always grab something there.
Clothing/Shoes/Weather Gear: Although San Francisco is a generally casual city, if you are planning to dine at high-end restaurants, definitely bring nice clothes and shoes (dresses or at the very least a nice top and black pants, nice dress sandals or heels for women; business dress for men, or at the very least, polo shirt and nice slacks). If you are not going to nice restaurants, or other dress-to-impress events such as the opera/ballet, etc., then San Francisco is a very accomodating city in terms of fashion. Anything seems to go here! Just make sure you are dressed warmly for San Francisco's unpredictable, often cold weather!
Luggage and bags:
Lock it up with a pad lock folks. No joke.
Clothing/Shoes/Weather Gear: Take some crapy clothes with you. Then replace them with new cool new ones you buy alone the way. Donate you old ones to a hostel.
Miscellaneous: And of coarse there’s this old one: “Lay out all the clothes you want to take with you. Take out half the clothes and double your money and you should be fine.”
Luggage and bags:
It is expected that you dress up if you are planing to go out to dinner... So on that note, bring a garment bag to put dresses/ suits in, or a hard shell suitcase.
Clothing/Shoes/Weather Gear: Don't let the title of 'SUMMER' fool you. Mark Twain once said "The coldest winter I ever spent was summer in San Francisco," and anyone who's been there will agree. The temperature will be the warmest in September and October leaving most travellers wondering if they should pack a bikini or a parka. You will definitely want to bring parts and a sweatshirt, no matter what time of the year you visit this gorgeous city.
Camping/Beach/Outdoor Gear: The water is very cold and unless you surf, sail , or are wearing a wetsuit I wouldn't go into the water. While outside I usually wear a light jacket or sweater... If you have one, a windbreaker would be a good idea to bring.
Miscellaneous: The temperature generally rises once the fog starts to lift, but that could be as late as 15 or 16:00 sometimes, so it's good to dress warmly, but also in layers that you can shed if it starts to get too warm.
In the autumn the city can still warm up. Bring layers of clothing: lightweight t-shirts, denim skirts or jeans, a sweater or a lightweight parka.
Above all, wear comfortable walking shoes. The hills are a killer. Women should save fancy shoes and sandals for evenings out only.