Sitting here in Pittsburgh where we had a very Summer-like Sat-Sun-Mon with temperatures in the 70's up to a high of 84 on Sunday afternoon.
Today it only got up to 43 and tonight there is a Freeze Warning with an expected low of 30.
We're almost in May. I've never seen this in this part of the country. Heck I never saw this when I lived hundreds of miles further to the North.