Northern PA weather

We just got back from a camping trip to World's End with our friends from Myerstown. As usual, the nights were a bit on the cool side. Wednesday morning it was down in the 40's. Part of the problem is that the camp ground is in a Vally near the Loyalsock Creek. on calm, clear nights not only do we get the normal heat loss to the dark sky, but all the cold air from the surrounding hills drains into the valley. Add to that, there was rain on Tuesday do we had evaporative cooling to add into the mix. Put it all together and we were glad we had a heater in the camper!!