Everywhere I look, it says DB (and ÖBB for that matter) release tickets for purchase 180 days in advance. I'm trying to purchase tickets over the Christmas holiday, when I know they run on briefer schedules, and so far neither site has anything past 12/8/18. Can anyone advise when later December tickets should be available? Thanks!
It's my understanding that European train schedules change each year about June 10 and December 10. That may be why you're not seeing anything later in December at this point. I hope someone else has knowledge of when you'll be able to order tickets.
DB's winter timetables will be available from 15 October.
"Everywhere I look, it says DB (and ÖBB for that matter) release tickets for purchase 180 days in advance."
I'm not sure where you're looking, but that's not correct.
Schedule changes are done twice a year; before schedules are finalized, no tickets are released.
Some trains are scheduled sooner than others. For instance, in Italy the long distance trains are done first, but the regional train schedules can be posted much later (sometimes just a few weeks before June or December).
Even once schedules are made, when tickets become available for various routes depends on the country and the route. For some it's 180 days; for some it's 120 days; for some it's 90 days. And this is referring to routes where advance tickets are available in the first place.
Just remember that if you can't buy tickets, neither can anyone else. Just check every day or two, so you can get to the first batch and get discounts.