How to change the weather from cloudy to sunny on a dedicated server - not a lot seems to work?

[Biglittle]

Hi guys, I have a dedicated server and wanted to ask if there is a way to make the clouds and rain stop or at least disappear as my server seems to be dark a lot of the time, I have tried the:
DM
F1
help weather

but that doesnt seem to work?

Is there a mod or another working form please? I have looked on the forum but couldnt see anything...Thanks.