we were actually in Baltimore during that 1994 cold outbreak. It basically never got above zero on the drive there from VA - Staunton had a low near -20F that morning. The Inner Harbor was frozen solid lol.
mean temps in the mid 30s is not "very cold for our area by any historical standard" in December. DCA finished the weak with a -7.5F departure, while IAD was -9.1F. Yes, that's cold. It's not earth shattering.