"I used to get the more distant FMs late at night, for some reason, of which I am not clear."
The sun offers a tremendous amount of interference on a broadband basis. When the sun is gone, signals propagate better. Groundwave at the radio horizon (and slightly beyond - don't ask for an explanation of the "slightly beyond" part) become more receivable because there is less solar interference (as long as you aren't close to co channel or first adjacent signals). If it's cloudy you can also experience E-skip skywave at FM band frequencies. Clearly not like AM channels, but the signals do bounce around when the atmospheric conditions are "thick."
I remember picking up 106.7 when it was on Mt. Scott down in southern Oregon on I-5 between Grants Pass and Roseburg as I was traveling north every time I would hit a hill peak and start coming down the north side.