I just came back from a 4 miler as the sun was setting. I heard it also briefly snowed in Toronto today. Anyways, it was freezing (well, almost). The temperature was 3 degrees with a windchill of -2. And I wore a long sleeve top, polypro gloves (lifesaver) and shorts (bad idea.)
Did 4.2 miles or 6.8K in 32:23, for a bang-on marathon pace run of 4:46 kilometres or 7:41 miles.
And for the Chicago folks, yep, on the weather, we feel your pain..