However, mods that don't interact with whatever they change could get by unscathed (I'm guessing clothing-only mods would be fine).Bethesda recently made a change like this to add skins to weapons in Fallout 4 and a ton of weapons mods had to be re-configured to use the new naming mechanisms. So, modders have to then adjust their mods to talk to the new game mechanics.
They will likely release a patch that manipulates the background mechanics of the game so it is capable of supporting the seasons, since that has not been part of the game yet.