[PaulDavisThe1st]

The US is generally at significantly lower latitude than Germany and other mountainous areas in Europe. This means that for large parts of the high altitude areas, seasonal variation in day length is much less than in Europe.

Also, because urban environments in the US west are relatively new, they tend not be found "between mountains" in the same way that the centuries old cities across the Alps etc. are. The large population centers (Denver, Salt Lake City, Albuquerque) are built in large, open flat areas, and many of the midsize cities are not really surrounded by mountains in the way that equivalent European or other non-American cities often are.