When it comes to flights over the Christmas holidays, you should book as early as possible. The airlines know they can fill every seat at a high price so they don’t have an incentive to lower fares like they do for flights in January or February. Air Asia now flies from the US to Asia and at good fares. Aside from them it’s just the major airlines as well as some Chinese airlines that do those routes.
November is a tricky month in tropical Asia, as you’ve discovered. In Thailand, Cambodia, and Vietnam, it can be rainy, and that includes some days where it rains the whole day rather than the quick cloudbursts you get in June and July. The best tourist beach in Vietnam is in a town called Nha Trang in the south, and there is Da Nang near Hoi An in the center of the country, but you’ll get November rains in both of them.
Your Munich plan sounds good. It can be fun to actually spend a full night in a town like Rothenburg ob der Tauber because it’s filled with day-trippers in the day and you almost have it to yourself at night. But it’s small enough that one night there would be enough. Nuremburg is quite a large city, and you might even stay there a night or two as well. I don’t know if I’ve ever heard of anyone saying they enjoy the cold and the rain, but if you do you’ll love it there. Fortunately, nowhere in the popular parts of Europe do they get extreme winters, and there is a good chance you won’t even see any snow in those cities. Most people are looking for the warmest places, which can be found in Portugal and Spain, but since that isn’t you I think your plan is good. Christmas is a big deal in some European cities such as Rome, but not a huge deal in others. Most businesses will be closed that day in nearly all countries, but of course hotels and many restaurants will be open. I hope this helps. Let me know if you have any other questions. -Roger
Traveling during the last ten days of December means crowds and exorbitant prices throughout much of the world, but the first two-thirds of the month—before holiday airfares and hotel rates go into effect—can be a serene, value-laden, and just plain lovely time to vacation. Europe is all decked out for the holidays—with locals generally friendly and in high spirits; in the Southern Hemisphere, spring is in bloom; and in the Caribbean, Hawaii, and Mexico, hurricane season is over, the weather is gorgeous, and there are free upgrades galore.