When staying at the Marin Vista House, a trip to San Francisco is usually in order. Driving on your way to the city through Marin you'll notice your driving through climate zones. In summer, Marin usually sits in the sun, and San Francisco can be a whole spectrum of climates, usually cooler. Vice Versa, in Winter, Marin is usually cooler than San Francisco, which can sometimes be enjoying more sun.
San Francisco's side of the Golden Gate in fog, Sunrise. Beautiful.
Here is an attempt to answer Marin Vista House retreat guests questions about Bay Area weather, particularly San Francisco and Marin. Because of the the Pacific Ocean, Mountain, and Bay influence, both places, though a short distance apart, can have very different weather patterns.
(See Marin Weather link for Marin Weather summary)
San Francisco's weather is very difficult to forecast, and differs from neighborhood to neighborhood. Due to the city being surrounded on all sides (except one) by ocean and bay, with some very tall hills in the middle, not one of the 4 seasons corresponds correctly to what the weather “ought” to be by definition. In the middle of summer downtown SF can be in the hot sun, but Ocean Beach, on the west side of town, is freezing in the cold fog.
To predict weather for San Francisco visitors is next to impossible. The only thing that one can expect from San Francisco is the rolling white fog, brilliant sunsets, and gorgeous views. But, if you know your areas, you can get the most of your visit to the Bay Area.
This summary is a San Francisco 4 season estimate only, and reader should keep in mind that seasons vary yearly. ;)
March - May
These are very inviting months to visit San Francisco. Not to hot, not to cold, but characteristically cloudless and mild. For San Francisco, not to be confused with Marin, South or East Bay, some of the warmest and driest days of the year occur in San Francisco's spring months due to the fog not rolling in as much.
June - August
San Francisco summers are not like summers elsewhere. Due to it sitting at the mouth of the Pacific Ocean, San Francisco is always marked by billowing white fog, sea spray, wind and Central Valley heat for it’s summers. Characteristically overcast and cool in the mornings, with the afternoons much sunnier due to the marine layer burning off. By August end, however, the fog thins and produces the iconic white finger of rolling white. The beauty of the rolling fog is unique and profoundly unique. Watch the fog pour through the Golden Gate Bridge, or see it just sit low on the San Francisco Bay; truly beautiful..
San Francisco is truly the best during Fall time. The days are warm and sunny. The nights are mild and clear, with people out and about. Rainfall is rare. The famous San Francisco fog has cleared and finally, San Francisco is warm!
Snow in San Francisco is rare, even in San Francisco's coldest months of the year, December and January. Rain, however, is abundant and storms from the moist coasts of Mexico and Central America bring anything from light showers to torrential downpours during these months. Winter temperatures in San Francisco are quite temperate, with highs between 55F and 60F, and lows in the 45F to 50F range (Null, 1978).
What to Pack when traveling to San Francisco.