It really is. Anyway, terms like “summer” and “winter” are always relevant and true if you just figure out where the event is taking place. Shouldn’t be hard. We simply cannot (and should not even try to) excise anything and everything potentially (usually not really) exclusionary from our lexicon as then we’d not be able to discuss anything at all.
In the future all dates should be given in all calendars, including the Elven Calendar, the French Republican Calendar, and by Stardate. You know, to be inclusionary.