I guess I never thought much about this but I guess it makes sense. Some guys around here were looking into building a trap range and said it must face north but I don't remember reading that but it makes more sense than facing west or east I guess.
Due to the arc of the sun, you get much better light on the target if you throw to the north. I have shot at clubs which face every direction. In Atlanta Ga. you shoot to the east and if the wind is from the east, you have a fine aroma from the land fill. I remember years ago, the club hosted the state shoot and recommended all the northern shooters squaded early so they could get home, ha,ha. A club in Maryland shot to the west. You did not shoot there after 4PM if you wanted to win.
The old Remington Gun Club in Bridgeport Conn was on a piece of land on Long Island sound that only allowed shooting East-South & West and the old Lincoln Park Traps in Chicago faced Lake Michigan so you shot facing East.
There is a MD club that faces East. My first time there, I was happy to get on an early squad (since i have young and active kids, my wife expects me to get my shooting done fast on the weekends). Needless to say, shooting into the morning sun reduced my scores. When shooting there now, I register during the last registration hours and get on the last squads.