Does it real? mages at each city manipulating the air temperature? Halone?
I'd like to think they hired black mages to influence the aether to create snow at the 3 cities.

So yes devs, please talk to us, we loved this year's starlight a lot but snow at the Eorzea city states deserves clarification. If it's just an illusion we can live with that.

What do you all think?