Indications that the temperature may be sliiightly sub-optimal

1. The insides of your nostrils freeze two seconds after you walk outside.

2. You study the campus map to take advantage of large buildings that you can walk through instead of actually going outside.
2a. You see your professor doing the same thing.
2b. You're both late.-

3. You know how when you were little, your mom ALWAYS insisted that you zip your coat ALL THE WAY UP? Past the point of regular dorkiness, to the neck, but all the way into supreme nerdhood by actually zipping it up the collar that goes past your nose?

Yeah.

While this is about as far from "socially acceptable" as Kraft E-Z Cheez Food Product is from a wheel of cheddar, the plus side is that no one can actually identify you.