I like very much this topic. It's very interesting.
It's true that clouds are always present. They seem to cover Ennis and Jack's lifes and only them !!! It seems to me that Ennis and Jack are wrapped as if they couln'd go out. A blanket of clouds. I remark that clouds are always motionless unless when they move in front of the moon. I have had an impression of increasingly fast rate, as what was going to happen under the tent, the first night of love. All was accelerated suddenly, even clouds.
Nature is the witness of this story, the only witness ( I remember the scene where the litte tent is isolated, lost in mountains, in a complete solitude having only for witnesses river, moon, trees and clouds.
For me, clouds are as "characters" : so silent, but telling so much.
Thanks Pierralex for this topic ; it was hard for me to translate exactly what I wanted to say...