Going to Disneyland in December...?

The Disneyland Resort will be in Full Holiday Mode at that time. It won't be as busy as it is during the actual Christmas period from the Weekend Before Christmas through New Years, but it will still be on the busier side. However, it should still be quite manageable.

The parks won't be open as late as they are on Weekends or during the full holiday, but you can probably expect both parks to be open until about 8-9PM. The other disadvantage is that the entertainment will be on a lesser schedule. Where at busier times you may get 2 parades, 2 Fantasmics, as well as the Fireworks. On the weeknight you will probably have 1 Parade and the Fireworks. Not that this is a bad thing..just something to be aware of for scheduling.

World of Color will be showing every night, but it will be the Holiday Version "World of Color - Winter Dreams". Since this will be the first year for this show it is hard to say if it is worth it or not, but either way you can probably expect higher than average crowds for these performances even on weeknights.

Last year they did have "Candlelight" performance every night which depending on the Narrator would cause some crowd issues, especially around Town Square. But as of right now they are supposed to be going back to the Traditional schedule of it being on the first full weekend in December which would be Dec 7th-8th. There were also rumors over the last year that some of their holiday entertainment would be moved to a after hours "hard ticket" event, however as of right now that does not seem to be the case for this year.

World of Color plays every night, even in the off season.

Fantasmic will be on weekends only. The resort should be in full Christmas mode, so there should be snow on Main Street and fireworks over the castle nightly.

Disadvantages? Not many. Candlelight is rumored to perform the 7th and 8th, so there shouldn't be any worries about congested foot traffic in Town Square.