Hi, I am trying to make plans for the winter but first I need to know what vacation dates foreigners studying Chinese have at Yunnan Normal.

This is what I can find on the U of Vermont's website (they have an exchange program with YNNU):
2009 Winter Vacation (12/12/2009-1/10/2010).

www.uvm.edu/~chinese/studyabroad/sld018.htm

But I am not sure if that is just for Vermont students or for all foreigners studying Chinese there.

Any info appreicated.

That is just for Vermont students. For everyone else at YNNU winter break will be from Jan 10 until March 3, give or take a few days depending on your final exam schedule. Obviously this doesn't apply to those studying one-on-one, where your schedule is taylored to whatever you want it to be.