sorry, i didn't make i clear,
you are right but that was just an example, i was trying to say,
<time> command <ammount>
where....
<time> = the time in seconds the weather will fade to the ammount specified, nothing to do with the time variable
<ammount> the ammount of change from 0 to 1
for example,
1800 setovercast 1
this will gradually fade the weather to 100% overcast, over a period of 1800 seconds