Aion 3.0 will have seasons.

In the 3.0 trailer some people noticed snowy weather in the new housing zones. Aion will have 4 seasons just like in the real world and they will correspond to certain in game months.

• Spring from March to May
• Summer from June to August
• Autumn from September to November
• Winter from December to February

No word yet on if these seasons will be limited to only the housing zones or if they will effect other areas of the game. Along with the snow or changing of leaves and blooming of flowers, at the beginning of each in-game month, there is a chance that special seasonal mobs will spawn in Elyos and Asmo housing zones. It seems these will be huge tree creatures which players can kill. I believe you can only do white damage in the housing zones so killing one of these mobs will take a long time or a lot of people. Killing them will rewards players with a random drop of a whale mount, packs of house decorations, as well as crystals and leaves needed for the quests for eternal wings.

Furthermore if these mobs spawn at a specific location (like near a certain lake) it will also drop additional rare items like eternal quality leaves needed to produce the Bike mount or other aether fragments which can be exchanged for rewards. As you can see because of its rarity, long spawn time, and huge demand, materials (leaves) needed for the Bike vehicle are very expensive…

It seems that, more season-related mini-events will be introduced in near future!  Thanks as always to Daeva's Report for having the awesome Aion info.