It's Called Synesthesia

I learned this week that perceiving letters or numbers as colored is known as synesthesia, and that perhaps three or four percent of the population has synesthesia. There is even an American Synesthesia Association, although I'm not sure why synesthetes need their own organization.

BTW, today--being a Wednesday--is a bright yellow day, but because it is the 19th, it also has tinges of orange and red.