Hours/Crowds first 2 weeks in December?

So for the first time in 5 years I am headed to Disneyland. The first half of December is always my favorite time to go, because of the decorations and holiday attractions, and the crowds are typically moderate, usually no more than 30-45 minute wait for most things (RSS not being one of those things.) But I'm planning to go the week of Dec 10 and I noticed Disneyland is open until midnight and California Adventure is open until 10 on weeknights. I do not remember the hours being crazy like that, I think Disneyland closed at 10:00 previously. I'm also finding it awkward that the parks close 2 hours earlier than this the week after... ummm, don't some schools start winter break that week?

Anyway, I'm just wondering how busy it's going to be. I find it strange that the weeknights on the week of Dec 10 have the same hours as Thanksgiving weekend.