If you're going to visit make sure you bring warm clothes. It's in California but it gets very cold there, particularly in the evening when the fog rolls through the Golden Gate bridge. This is especially true in the summer when fog covers the city most of the time.
Updates
Very true! For those seeking sun June through August, try one of the recommended trips away from the bay--wine country, Yosemite, and sometimes Muir Woods and the Berkeley Hills. July and August temperatures will often reach 100F in these areas. (For beaches, keep an eye on the weather report, as the Marin and Santa Cruz coasts are more likely to be warm than the bay.)
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