I’m planning a December trip (either 1st or 2nd week) and I wanted to know how accurate the crowd calendar is right now? What are the chances of it changing (or it being updated) from here until then?
It will be updated and that might cause changes
When can I expect the calendar to solidify?
Right now the Crowd Calendar is accurate enough for you to start doing some initial planning, such as picking weeks to go or making some preliminary park day decisions.
The major changes in the CLs are tied to WDW releasing and updating park hour schedules. The first update will occur when WDW releases the initial schedule for December, probably around the middle of this month. This is usually first released on the TA calendar, which is located at http://media.disneywebcontent.com/StaticFiles/ParkHours/WDWTravelAgent_December.pdf (currently showing December 2015)
The next big CL update will be about two weeks before the start of them month, when WDW usually does a complete update of the schedule. See http://blog.touringplans.com/2011/07/18/interpreting-park-hours/ for more details on the WDW park hours updating process.
Also, a good thing to do is to "track’ your days in the Crowd Calendar - this way you will get e-mail alerts when anything is updated.
Thanks ! I appreciate that!