I'm a dingus and just forgot to wake up on saturday. I only just now watched it. It was... kind of dark. I definitely enjoyed it but the seriousness of it startled me. It was fun.
If this really is their "first winter together," that means the entire show so far has somehow taken place over just one year. Unless Season 1 started in super early spring and left huge gaps to get to winter by mid season, then every other episode after that happened in very close proximity to each other to put off next winter until season 5, in which case the whole show still only takes place over two years.
Then there's that inconsistency with Hearth's Warming Eve that really bothers me. Maybe Hearth's Warming Eve doesn't really happen in winter? Ponies control the weather, maybe they make it snow on that day only? For some reason? I hate to think the writers of this episode just overlooked it.
Maybe years in Equestira are longer than in the real world? Maybe not every year has a winter?