In the Fog

Long time TF6S reader, frequent commenter, good friend and long time Bay Area resident "Penelope Pitstop" fished out a great article in the SF "Comical" about the worst summer weather San Francisco has seen in a long time. I've been waxing restless about the grey skies, cold wind and overall depressing fog that has enveloped the city since May. It makes a man want to get up and move to Cabo...or Fiji.

For those who have never been to the City by the Bay, first-of-all shame on you, and second, you'll have a hard time wrapping your mind around the microclimates here. For instance, this morning in San Francisco, the fog is pretty thick and keeps the city at a cool 58 degrees. However, if you drive across the Golden Gate Bridge for about 10 minutes, you'll see clear skies and weather well into the 70's. During the day it'll reach the high 80's or low 90's.

To this day, I still giggle at the tourists standing in line wating for the cable-car in shorts and t-shirts freezing their arses off. There is a reason why there are about 400 sweatshirt vendors down at Fishermans Warf. If you have a friend that has a "San Francisco" sweatshirt, chances are they didn't read their Lonely Planet Guide and weren't prepared for their "summer" vacation here.

So, why does this happen? Why is San Francisco so bloody foggy when everyone else is basking in the sun? Here's the explanation:

How fog is formed and why it moves from the coast toward inland valleys:

1 Winds around the Pacific High (a semi-permanent area of high pressure), circling clockwise due to the Earth's rotation, push ocean surface waters south and away from the coast.

2 The resulting current causes an upwelling of cold water from ocean depths.

3 The cold surface water cools the air above it, causing its moisture to condense into fog.

4 Warm air in the sun-heated Central Valley rises and is gradually replaced by cool ocean air, which draws the fog across the bay and toward the valley.

Even within the city, which is a surprising small little 7x7 mile block on the tip of the penninsula, there are many microclimates. For instance, I live on the East side of Russian Hill. By the time the fog gets to me, it has to cross three major hills. Other neighborhoods in the western part of the city that are unobstructed to the ocean sit in a dense fog for most of the summer. Usually, the fog "burns" out by the time it hits my house. This year, no dice. The fog has invaded and occupied the entire city.

Anyway, we'll get our summer next month. I need to wear this banana hammock speedo at somepoint this summer.

On second thought, I'm not European, so I'll leave the speedo at home.