Aaron Hurwitz asked:
Why are valleys colder than areas that are higher up?
Okay. Thereís a secondary effect. The world is far more complicated than youíd like to think. That tends to be because cold air falls. So, the valleys at low places on average are warmer. But if you got somewhere which is high up and the air can cool down on the tops of mountains, itís then denser around it and it falls downwards and if itís not falling very far it doesnít compress very much, doesnít get very much hotter so you get, locally very cold air is in bottoms of valleys but globally itís warmer low down and colder higher.