Isn't it a little too convenient that huge events on a starship/starbase always just happen to occur at the end of the calendar year?
That's just because of the 1,000 stardates-per-year rule which is not totally reliable. You could say for every network television show outside of Trek: Doesn't it seems strange that big events always happen at the end of May?
In Star Trek's case, we can assume this is only done so that historical events (from the characters' perspectives) have a convenient point of reference for our comparatively primitive system for keeping track of time.
I remember mentioning this in the Star Trek Magazine a while back, and pointing out that December is probably *not* a holiday season in the 24th century!
So long as events didn't impact on ship/base operations I'm pretty sure a whole array of holidays, celebrations, festivities and shindigs take place on Starfleet postings. Even though I find it a non-event, the New Year would be 'celebrated' by many species (and since they work by an Earth calendar then December 31st would be of some significance).
From a real-world perspective, the thousands place goes up at new year, but there has been nothing in canon relating stardates to any particular planetary calendar.
We have a few datapoints of stardate vs. calendar date that suggest the zeroes roll over in late summer - that is, when the television season rolls over. - It's definitely a winter sky we see over France in "Family", just after the SD-year-splitting "Best of Both Worlds". - The Diwali, an October-November festival, is celebrated in "Data's Day", on stardate XX3390. - First Contact, on April 5, is commemorated in "Homestead", on stardate XX868. Interestingly, there are basically no datapoints that would contradict this, even though no doubt several writers must have been living in the belief that the beginning of a season takes place on New Year on Earth. The vast majority of writers, plus the guardians of stardates, must thus have thought in terms of airdate instead... Timo Saloniemi
...After a night's sleep, the flu seems to release its grip, and I notice that I claimed no datapoints against stardate years rolling in late summer, right after establishing the datapoint of a winter sky in "Family". That one is the only datapoint I know of that would support the idea of stardate years rolling with Earth calendar years, though. And even though it's a winter sky, the landscape doesn't indicate winter in LaBarre, France (but with climate control, how could one tell?). Oh, well. Timo Saloniemi