How does placing telescopes higher eg: in the mountains above weather systems make observing easier?
There may be other reasons too, e.g. more space available to build larger telescopes in the open country.
There are a number of reasons. It's not so much the lack of clouds, although it's obviously good to have clear skies. But the air is thinner and there's less atmosphere for the light to pass through, so less light is lost on its way to the telescope making images much clearer. Also being far away from cities reduces the amount of light pollution from city lights getting in the way of what you want to look at.
thank you very much sir