Alcatraz Weather and What to Wear (Hint: Layers!)
Always bring layers of warm clothing on a trip to Alcatraz, even if the day seems nice in San Francisco. The fog likes to creep into San Francisco Bay at different times, and when it does Alcatraz is directly in its path. The temperatures can drop rapidly even as the wind comes up, creating a one-two punch that can make your teeth chatter.
Insiders Tip: During the summer and autumn a sweater covered by a windbreaker is more practical than a heavy coat, which you have to carry when it’s sunny and warm. The windbreaker can be folded to a small size and stuffed into a purse or backpack, and the sleeves of the sweater can be tied around your waist. If the fog comes back in you can add one or both layers and be warm again.
Alcatraz is a small rocky island in the middle of San Francisco Bay, exposed directly to the opening to the Pacific Ocean that is spanned by the Golden Gate Bridge. For this reason its weather is influenced both by the Bay and by the ocean and its banks of fog.
It may sound illogical, but summer is actually the foggiest part of the year on San Francisco Bay. We almost never get rain during the summer, but we can get wild swings in temperature.
In many years September and October are our warmest months, as the fog recedes and the long days still give us plenty of sunshine.
During the winter we have less fog on Alcatraz, but we’ll get one, two or even three days of rain at a time as Pacific storms cross the area.
A winter visit to Alcatraz allows you to buy tickets without ordering several days in advance, as opposed to the summer, when some days or parts of days can sell out.
Insiders Tip: Want to make sure you get a dry weather day during the winter? Buy your ticket “at the last minute,” and you can avoid coming on a rainy day, or at least know in advance that you need to wear a good raincoat. Last minute tickets may be limited on summer weekends, but during the winter they’re almost always available.