I am continually amazed at the variety of climates going on in the San Francisco Bay area all at the same time.

This phenomenon is due to the fact that this area is bounded by the ocean on the west and by hills on the east, with combinations of both elements inland in various directions. It’s a complex physical environment which results in many different micro-climates. It can be cool and foggy on one side of a hill and hot and sunny on the other side.

Here at the beach in Pacifica, just south of San Francisco, it is usually foggy and cool. The temperature usually stays in the 50s when the fog layer comes in.

James drives me over a rather steep hill to the north when he drops me off at the BART station to go to work. When there is fog in Pacifica, it is usually at its thickest at the top of this hill. Then we go over the crest and downhill towards the intersection of highways 1 and 280. Suddenly the hills to the east and the City to the north come into view, in blazing sunshine.

This does not always happen, but often enough to be a pattern.

Sometimes the fog stretches northward past Balboa Park. When I ride the train, I’m not sure where the fog ends exactly because BART is underground after that station. But it is frequently sunny in downtown San Francisco when I emerge to street level at 7th & Market.

The fog creates changeable weather conditions very quickly. James told me the other day that there were at least three short periods of sunshine yesterday at the beach, none of which lasted more than an hour, and usually much shorter.

So if you don’t like the weather, stick around a minute!

I was amazed this past summer at the variations of temperature around the Bay area, even when it was sunny everywhere. It would be 60 degrees at the beach and over 90 degrees a few miles inland.

My friend R.A. lives in Lafayette, at the extreme eastern portion of the Bay area. You have to go through the Caldicot Tunnel, which cuts through a major range of hills separating Oakland from the rest of the East Bay, to get to Lafayette. The western side of the tunnel would be 70 degrees and the eastern side twenty degrees warmer. Then it escalates quickly as you proceed further east.

There is often a 50-degree difference between San Francisco and Sacramento (90 miles inland) in the summer.

I have a theory why Pacifica is such a laid-back, unpretentious community. It may be totally off the mark but it entertains me to think that it’s because the area is so foggy. If it were brilliantly sunny here by the beach all the time, it would attract wealthy people wanting to build fancy homes overlooking the ocean.

Obviously, Pacifica residents don’t mind the fog. James and I can tolerate it for a few days in a row, but it gets kind of old after two straight weeks, which happened in mid-July. It was maddening to be stuck in fog all day and then drive over the northern hill to find blazing sunshine, barely two miles away.

So I suppose the remedy is to get OUT of the house and take the train to more sunny environments. In the San Francisco Bay area, you usually have not far to go!