Couple things.
Clouds are actual objects tied to the map itself.
Server must enable Clouds in the Misc. Difficulty section (and client should as well).
And
server should have
typeclouds=1 in their conf.ini
Code:
TypeClouds=0 - standard clouds
TypeClouds=1 - improved quality clouds
I also believe checkruntime=1 (or maybe 2) is required.
I've noticed that I can have simple clouds on when others can have the more comprehensive clouds in the same game.