Hello ShannyRose! Currently we offer seasonal changes for two of the Linden Homes themes: Aspen Ridge and Fantasy. Aspen Ridge is a bit more realistic, with snowy roofs recently added to the content pack for that theme. Fantasy regions enjoy seasonal coloration, with winter being a nice icy blue. :-) We may create new themes with these types of features in the future.

In the meantime, you may decorate within your parcel as you prefer (check the covenant for some guidance on content!).

We'll mark this as tracked, in case any updates to existing themes might include adding the scripted content required for seasonal changes. Thanks for the suggestion!