Are Uggs good for Washington D.C.?

Well, technically theyre fake uggs, but still the suede boots with fur lining. I'm going to the inauguration in january, and I dont know how warm/snow proof uggs are. Since I'm going to be standing in the cold for 6+ hours, I need to make sure I'm as warm as can be. So are Uggs ok, or should I just buy some snow boots?