The official Cities Skylines Twitter account has posted a cryptic announcement that seems to indicate something weather related is being included in the game tomorrow.
The tweet asks, "Something is happening tomorrow. That something is a thing and that thing you will know soon. Are you ready?" and links to a pic on Ow.ly featuring Chirpy (the game's version of the Twitter bird) wearing a wool cap.
This would seem to indicate that Cities Skyline is getting either weather effects or even seasonal effects that the player must now account for while running their virtual town. The last expansion, After Dark, expanded on the effects of a day-night cycle.
Stay tuned, as GameWatcher will be ready to find out whatever it is Paradox Interactive has in store for the game.