So this isn't super exact in the common usage of calendars, in part because calendars are usually implicitly fixed to a timezone (hence Google Calendar asking t

So this isn't super exact in the common usage of calendars, in part because calendars are usually implicitly fixed to a timezone (hence Google Calendar asking to change your calendar's timezone). For example, December 25th might be Christmas, but you cannot define two Dates that "delineate" Christmas in the world, because the start time is different dependent on the time zone. While this is kinda pedantic to Earth calendars, it's also the kind of problem that most commonly causes issues in our programming. You can do "if date < christmas", but it most likely won't do what you want it to do if your program is meant to run in many timezones.