Summer in Orinda can sometimes be 30 degrees warmer than San Francisco, where I work. It’s less than 20 miles away and a pretty short BART ride.
Even just 5 miles away, Oakland and Berkeley can be 20 degrees cooler.
That finger of fog comes in through the Golden Gate bridge and comes in directly toward Berkeley’s Greek Theatre. It then comes over the hill once the SF Bay proper fills up with fog.
This means it will be gray and cloudy and dark in San Francisco and in some parts of the East Bay, but when I get off work and arrive at the Orinda BART platform, I have bright sunlight and cool clean air conditioned air.
These are my favorite days of summer.