Facts of contrails

Originally posted by Zaphod58

Originally posted by MountainLaurel
Still would not explain what I'm seeing in CA, with warm weather and generally low humidaty here.

That's just it though. Ground level conditions don't mean anything when you're talking about 30,000+ feet. I came through Arizona yesterday afternoon, where the humidity was low, and the temp was in the 90s (according to my truck sensor), and watched a couple of dozen persistent contrails being left behind. Including one that started from "nowhere" made a dogleg, and persisted for a way before stopping. Just normal contrails. Really pretty at sunset.

I agree. When I flew the Cessna in my pic we flew at 1800 feet and it was just barely light jacket weather on the ground. we were blasting the heat at 1800 feet. Didn't really notice how high the heat was until we landed and I started scorching..

reply to post by phroziac


And it's normally -40 to -60 F below zero at 35,000 feet (a typical cruising altitude for airliners) -- even on a sunny and warm southern California day.

Originally posted by Aloysius the Gaul
US Statistics in fuel use by different types of transport per-annum since 1960

this link has changed - US statistics in fuel use by different types of transportation per annum since 1960