Is the second week in December a good time for a cruise?

The short answer is that any time you can take a cruise is a good time.

The longer answer is it depends on where you want to go. If you want to get out of colder weather and visit the Caribbean, it is a great time. If you are headed to South America where it is summer, it is a great time. If you wanted to go to Alaska or do a Canada and New England cruise, that is not so great. In fact, you won't find any cruise line offering those cruises during the second week in December.