CTP answered this for MDT - but the city has been a degree or two warmer all summer. They tweeted:
This morning at 6:56 AM the temperature dropped to 69.1 degrees at Harrisburg International Airport (KMDT). This is the first reading below 70F at KMDT since July 18th. It will be noticeably cooler across PA tonight with temps dropping into the 40s in the northern mountains!
I believe so - not sure if I got below 70 in all of July actually. I don't keep records though.
Just think - in about six weeks we can start tracking arctic air plunges!