Relax, don't overdress, dress lightly so you don't end up sweating all over the place.
One thing I hate about the offices where the interviews are conducted, and I have seen this at Jefferson and LIU, is that they are way too warm. 75 degrees without having a fan on is way too damn hot.
I walk in from the outside, which is a comfortable 20-30 degrees Fahrenheit, and I expect not much of a temperature change, then I get in and the heat is on full blast, I start sweating like crazy. Yes, I think below freezing is comfortable, I'm a cold weather lover.