San Francisco is a popular destination not just for tourists but also for the convention industry.  SF has over 30,000 hotel rooms and at times during the year, conventions that have 15,000 or 20,000 or 30,000 visitors can raise hotels rates.  A smart visitor who wants to save money checks the convention calendar and makes SF a vacation spot outside the dates with large conventions.  
If you have a reservation for a hotel already, when the conventions are in town, fear not.  Most of the convention folks are sleeping with their eyes open inside the Moscone Center and they often don't stray too far from the area.  Visitors may have some issues with dinner reservations around the immediate area, but there is room for everyone in other parts of the city.

Please note -- The conventions calendar has a list of meetings and conventions throughout the year.  Meetings with 15,000 and above visitors may affect the Union Square hotel prices.  Smaller conventions should not cause a hike in hotel rates

  Have a look at this HOTELS AVAILBILITY LINK from the SF Travel bureau




Weather Advice  (Advice from DEs White Dahlia, Holodan among others) 

Visitors should plan for some cool weather almost any time of the year since some early mornings and evenings will be cool during any season.  Because the temperature may vary throughout the day and between neighborhoods, dressing in layers that can be added or removed is advised.

Different seasons in San Francisco bring different weather. Even if the temperature differences between different seasons aren't as great as other places in the U.S., you'll see some patterns.

  • Spring -- Early Spring is often cool and rainy.  San Francisco rain is mainly drizzle with intermittant showers.  Even on a rainy day you may see some periods of sun. Late spring may have some beautiful days, fog is also a possibility.
  • Summer -- The famous San Francisco fog rolls in. It is easily among the coolest places in the USA during that season but you're unlikely to see rain.  Mornings and evenings are often the most foggy and it may "burn off" during the day. Even when clear of fog, the temperatures usually remain cool.
  • Fall -- Lovely weather, Hardly any fog to be seen and often the warmest time of the year. 
  • Winter - Cool, cold and windy especially on the Bay.  The main rainy season--which means drizzle and occasional showers. You may also see some clear days between rainy ones. Daytimes are in the 50s F and nights in the 40s F.  It does not snow in San Francisco.

Weather Forecasts   Weather underground

September and October is most likely to be the best weather, but hotel prices around that time can be very high because of the many visitors who come then; even budget hotels that are normally $100 to $150 may be 2 or 3 times as expensive.  Mid-range hotels may charge over $500 a night when demand is high. There is really no reason to get a cheap flight and counteract the savings with these kinds of hotel prices, so it's a good idea to check hotel prices before locking in your flight dates if you're worried about your budget.

The spike in rates has a lot to do with many large conventions during early Fall (check the convention calendar above).  Also realize that the good weather means late Summer and early Fall is a popular time for many festivals and street fairs.  Some big yearly events during the time include Outside Lands, Hardly Strictly Bluegrass, the Treasure Island Music Festival, Fleet Week, Folsom Street Fair and the Nike Women's Marathon.  These events put upward pressure on hotel prices in addition to the large conventions.

You may be able to find better rates by scheduling between large conventions and other events, but many convention-goers stay before or after events for some personal vacation, so lower rates aren't guaranteed and it may be difficult to find a lull.

There are a number of events that bring visitors to San Francisco at any time of year in addition to those listed above. For example, Chinese New Year, Pride, marathons and film festivals. There is always something going on in the city.

By early November hotel prices are often better than September and October, but if you delay until Thanksgiving (the 3rd Thursday) flights may be full and much more expensive. The first week of December can be a lull in travel -- before Christmas travel season really gets revved up. And yet Christmas decorations and lights are all up which makes for a festive atmosphere. That time period is heading into the rainy season so there are risks of wet weather.

The days around Christmas (plus or minus 2 or 3) have some of the lowest hotel prices of the year. Even luxury hotels are available for a bargain.  SF is lovely at Christmas and it's a great time to visit Union Square and other parts of the city 

January/February is the heart of the rainy season. There can be some real gully washers but they may be followed by a few days of glorious bright, clear winter days. 

March - May can be nice. You may encounter some rain in March, or later, but *usually* the biggest storms have passed by mid to late Spring.

Spring , Summer, Fall, Winter -- Anytime is a good time compared to places with less mild seasons. If you want to beat the heat in Europe or other parts of the USA (including other parts of California just 50 or so miles away) San Francisco is among the coolest places in America in Summer.  While locals complain about the cool temperatures and Summer fog, many visitors find it a nice relief from the Summer heat in other places.  At any time of year, don't forget to bring long pants and a jacket or other layers that you can add or remove to stay at a comfortable temperature.