tire pressure

Thanks everyone.  I found a place close enough to fill the tires that shouldn't heat them up much.  I will check my gauge against the one there; heading there soon.  I do not believe the tires are filled with nitrogen.  I have seen no indication of such.  Its not surprising to me that the tires are low.  While new to me, this is a 2016 that seems to have not had much attention at all at least over the last 1.5 with a second owner.  The tires were replaces by the first owner in 2017.

Why does pure nitrogen as opposed to an 80% mix stay in the tires longer.  Does that 20% of other gases leak out easier?  Just wondering. 

You can also pick up a nice little portable air compressor from Target, HD, Lowes, or Walmart for between $30 and $80. Most of them run on 12V, and a couple also have 120VAC input. Some will also have a built-in flashlight and/or carrying case. Most are pretty small; smaller than a bread box. They're not fast, but you can use them almost anywhere.

Regardless of what your tires are filled with, its a good idea to cross check tire gauges. The cheap gauges are notorious for being inaccurate. Also, be sure to get the gauge pressed onto the valve stem straight and hold it there for a second or two.  If you hear the sound of air leaking out during the pressure measurement the gauge will likely read low. 

For tires, 'cold' means not having been driven on, or heated up, in the last several hours.