It should also affect production of resources, troop effectiveness, building speed, etc. I like it but should only be world exclusive like say World 105 would have weather enabled and then World 106 not.
Suggestion on weather effects:
Sunny - increase clay production by 2%, troop speed increase by 3%, building speed increase by 3%
Cloudy - increase wood production by 2%, troop speed decrease by 3%, building speed increase by 3%
Snowy - increase iron production by 2%, troop speed decrease by 5%, building speed decrease by 1%
Duration of weather:
Ranging from 1 day - 5 days with 1 week buffer for each weather