Ok just to make this clear. The existing mmo map will be the starter area and is nothing compared to the actual mmo map, wich will have all kinds of biomes.
the existing one already has most kinds.
also, there already is weather in game that influences the amount of crops you harvest.
its just not visible yet.
to answer the topic, mmo will propably come out mid 2015,
as bobik stated somewhere.
Btw if you want to have some information on planned things check out the FAQ, it will has tons of infos to offer