Older kids will appreciate the city's historical and cultural significance and can easily handle the rolling topography that San Francisco is famous for. Although younger kids will tire quickly on the hills, they'll get a kick out of the city's oddities (street performers at Fisherman's Wharf, bison in Golden Gate Park) and a ferry ride in the Bay.
San Francisco is a great place to visit any time of the year. Street life abounds, and there is usually some type of festival or street party. The September to November period is particularly festive and this is a great time to visit -- as is just before the summer peak season. Since outdoor activities can be enjoyed year-round, you really can't choose a wrong time to visit.
Mark Twain ("The coldest winter I ever spent was a summer in San Francisco") was right -- it can get really, really chilly when the wind picks up in the afternoon and the fog rolls through the Golden Gate. They don't call it "the Bay Area's natural air conditioning" for nothing. Make sure everyone in the family ties a warm sweatshirt around their waist every day when you leave the hotel, and wear layers for seaside destinations such as the Golden Gate Bridge or Fisherman's Wharf. Temperatures are best September to November, when they're around 68 degrees, but other seasons can be found here.
There are three airports in the San Francisco Bay Area. San Francisco International Airport (SFO) can be more convenient for those staying in the city, but Oakland (OAK) and San Jose (SJC) -- about an hour's drive -- tend to offer more discounted flights. San Francisco and Oakland airports are connected to the Bay Area by the BART (Bay Area Rapid Transit), which is fairly easy to navigate. Taxis are widely available and both Amtrak trains and Greyhound buses serve the area.
San Francisco is a commuter-friendly city, with an extensive public transportation system known as "Muni" (San Francisco Municipal Railway). It operates buses, electric trolley coaches, streetcars, and of course the world-famous cable cars. BART trains operate within the city and to San Mateo, Alameda, and Contra Costa counties. Driving in San Francisco is not recommended; parking is more than a hassle and with so many taxis and public transportation options, renting a car to get around is an unnecessary expense. However, if you are planning to take any day trips outside of the city, renting a car is the way to go. Visit Transit.511.org to see every transportation option within and around San Francisco.
The San Francisco calendar is jam-packed all year with celebrations, some of which draw visitors from around the globe. Dates vary each year, so check official event websites or call the Chamber of Commerce for exact dates.
The San Francisco CityPass is an all-in-one pass to some of the city's most popular museums, including the Exploratorium and the Legion of Honor.