From what i can tell, the weather is determined locally by your client.
That means there might actually be a way to control the weather.
http://forums.elderscrollsonline.com/discussion/122684/ineresting-observation-about-time-of-day-and-weather/p1
@GnatBDon't see how that thread indicates anything of the sort. Just that PTS shares the same day/night/weather cycle as regular servers. Could just mean that it's all based on the clock/weather where the servers are located or somesuch.
Should be easy enough to actually tell if it's clientside though, wait for it to rain, and ask folks in chat what kind of weather THEY are seeing. Assuming no trolls, if they say something different, then it's not client side.
I agree (to an extend). You can change your computer time and timezone and the weather and daytime will not change.@SirAndy Gonna go and throw a monkey wrench in your theory there. My SO and I play the game together, within the same household and our weather frequently does not match in game. So it's not based on your real world geographic location. I have no idea what it's based on to be honest.
I find the revelation that weather effects are client side amusing. This means that those on the forums who complain about constant rain literally have their own private Eeyore cloud following them around. :P