My Step 2 CS score won’t be available until December. Should I apply now or wait?
The answer varies by individual program. Some programs do not list passed Step 2 CS as interview requirement, some do. The best way is to check with each program and apply only to those that do not require Step 2 CS for an interview. As for the other programs, you should apply after you get the result assuming their application deadline has not passed.
The most reliable way to get this information is by calling the programs. If you have no time for calls, http://www.residencyplace.com search engine can narrow your selection by programs that do not require Step 2 CS for an interview: https://www.residencyplace.com/PathFinder/ProgramList.aspx
Click on the "Search By" link and select "Residency Preferences" for the "Passed USMLE Step 2 CS" line.