[Norck]

Function SetWeather(id) (https://sampwiki.blast.hk/wiki/SetWeather) changes a weather instantly, also this is the only one way to change weather. Seems that you have a timer which changes weather after certain amount of time. Anyway, to change weather, simply place

pawn Код:

SetWeather(id);    // id = weather id

at the place where you need to change a weather (some command, for example).
You can find a list of weather id's here:
https://sampwiki.blast.hk/wiki/WeatherID