The Sun doesn't get very high in the sky here in Colorado.  It never really is directly overhead because technically it doesn't get directly overhead anywhere in the continental U.S since the Earth's rotational axis is tilted 23.5 degrees with respect to its journey around the Sun, so you'd have to be less than 23.5 degrees above or below the equator for the Sun to be directly overhead.  The Sun's rays shine at a smaller angle here and thus the energy is spread out over a larger area making it weaker.  Stacie and I often talk about how God has placed the Sun exactly where it needs to be for us to exist and when you stop to think about it, that is pretty amazing.  NASA announced that they have figure out how to travel to the Sun.  They're going at night.  Have you ever seen an eclipse?