Cities: Skylines - Snowfall

In Snowfall, the difficulty heats up when the city cools down, thanks to a new in-game temperature reading that will have residents bundling up for warmth when the weather outside is frightful. Cosmetic weather, composed of rain and fog, will be added to Cities: Skylines as part of a free update.
Players who own Snowfall will get to face new challenges such as ensuring that their city infrastructure can handle seasonal heating demands – and, when the snow starts falling, that the roads can stay clear. New snowplow services will be required to prevent traffic from freezing in place, while new all-weather trams and expanded public transit options can help residents and visitors alike get around town – and visit the new winter parks and landmarks available in Snowfall.
Now is the Winter of This Content: Rain and fog for existing maps, plus a new “Winter” map theme with snow and all of its challenges.
The Streetcars You Desire: Expanded public transportation options, including easier management of existing lines – and Trams, a new system demanded by fans.
World Warmth, Too: Cold weather increases demands for electricity, unless new water-based heat systems are in place.
Plowers to the People: Build a snowplow depot to keep traffic flowing during winter weather, and employ new road maintenance systems to keep your streets in shape.