I moved from Seattle about three years ago. We definitely had many foggy days there. Here in western North Carolina, we also experience a lot of fog it gets caught between the mountains. We’re close to the smoky mountains, and it is fog which makes the illusion of smoke.
However, I want to discuss what we MSer’s call cog fog. The National Multiple Sclerosis Society has some very good information about how cognition is affected through the breakdown of nerve signals. You can find it here. This article talks about information processing, memory, attention and concentration, executive functions, visual perception and verbal fluency.
As a funny and self-deprecating example, I got up early one morning to go swim. I had my gym bag packed and went into the garage to open the garage door. I pushed the garage door button and the garage door went up about 8 inches and then back down again. I tried it a couple more times. But nothing worked. We found out later we needed a spring replaced.
What makes this an example of a foggy brain is that I could have walked out the front door as my car was parked on the street. Instead I turned around and went back to bed!