When Are Fall Semester Grades Usually Issued?
Fifteen December is, indeed, a bit early. Final exams often come about then and professors have a week or so to submit grades. After that it goes pretty quickly with modern automation. But 31 December would be more realistic. 

But even then, if you request grades formally, it may take a bit longer for them to be sent and received. 

There are still some US schools in which the "Fall" term doesn't actually end until about mid January.