high season: May to October
shoulder season: November to April
Weather InformationThe temperature doesn't fluctuate much, so to visitors, San Francisco seems warm in the winter and cool in the summer. Summers tend to be foggy, though the fog burns off eventually, which can lead to stretches of great weather. The nicest time of year tends to be during August and September, when days are often warmer and the fog isn't as prevalent. Insider advice: Just remember to layer.
Crowd InformationSummer is a popular time with visitors, so expect crowds, especially on weekends. Most hotels and tourist attractions see high visitation during the summer months. The Moscone Center/South of Market (SoMa) area gets busy during the fall convention season.
Closure InformationAttractions may have reduced winter hours, and some close on major winter holidays. Some museums are closed one day per week, often on Mondays or Wednesdays. Except for a night bus, public transportation stops running around midnight or 1:00 a.m.
When to SaveTravel providers such as hotels will sometimes offer deals to entice travelers during the off-peak months of December (except around the holidays), January, and February. Food prices and attraction admissions, however, remain constant throughout the year, with the exception of Dine About Town in June, when meals at some of the city's most prestigious restaurants are available at a discounted price.
When to BookWhile the general rule is to book early during peak times, different components of the booking process might require specialized approaches. Air travel is often cheapest when booked at least 21 days in advance. For travel during June, July, and August, it's a good idea to book a few months ahead. According to many area hotel employees, more and more people tend to book only a few weeks in advance. But remember, weekends in summer can still fill up early, as do other popular holiday periods. Also, how far in advance you should book accommodations depends on where you want to stay. If you're looking at hotels in a popular tourist area such as Fisherman's Wharf in the summer, it's best to book well ahead. The same is true for the area around Moscone Convention Center during September or October, when business travel peaks.
Information provided by the San Francisco Convention & Visitors Bureau