On Friday, January 29, 2016 at 6:13:32 AM UTC-5, wrote:
I keep my air compressor in the house or it wont start or the line
freezes. To pump up a tire, I have up to 165ft of air hose. Normally my
50ft and 15ft coupled together will reach my truck or tractor.

Anyhow, the air coming from the house is warm, (60 to 70 deg F). When
the outdoor temperature is zero or colder (F), that heated air is going
to change in pressure when it gets cold. I cant determine if the tire
will gain or lose pressure when the air gets cold. I'm sure it's not a
significant amount, but I'd like to compensate when I put the air in the
tire.

But which way, up or down?

Figure it out based in the info found he

http://www.tirerack.com/winter/tech/...jsp?techid=147