tfleeger wrote:
80%...That just sounds silly. The PSI difference at even 10,000ft is only approx 5 psi less than sea level. If anything, I would think you would want to increase your tire pressure a few PSI, assuming you pump up your tires at altitude, although personally I wouldn't sweat a couple PSI either way.He wasn't talking about tires.
Considering that the atmo pressure at sea level is 15 psi, reduction by 5 psi means 66%. What sound silly? That it's 80% at 6000 feet? Because it IS right around 80% at 5000 feet:
Edit changed this to a link it was messing up the formatting:
https://upload.wikimedia.org/...ure_vs._Altitude.png
Now, why weather forecasts do not reflect that I don't know either. Right now in Boulder CO (at 5600 feet) the forecast says 29.76in or 1002.1mb which is very nearly sea level pressures! The pilots correct for altitude and temperature (google density altitude). Maybe weather people are doing something similar? My bro is in NWS. I can ask him.