If you don't know it's hot today, just step outside. If you can't stand the heat, come on over to the Mudd (bring your parka) where you can observe library staff crouched over their PCs wearing Bob Cratchit-style fingerless gloves or huddling in front of the microwave for warmth.
Wisconsin's governor, Jim Doyle, has declared today Heat Awareness Day. Read the official proclamation while listening to:
Heat Wave (Irving Berlin, not Martha and the Vandellas)
Too Darn Hot
Steam Heat
Fear No More the Heat o' the Sun