Do Mountains Really Make Their Own Weather?

https://outdoorsfaqs.com/do-mountains-really-make-their-own-weather/
Weather conditions in the mountains are caused by several major local factors that include altitude, related temperature and humidity effects, local geography, and winds.

So, do mountains really make their own weather? My short answer to this is yes. Now, why this is so? In most cases it is easy to explain, but not in one sentence of course.