The month of June, which began with two weeks of very warm and frequently hot temperatures, has now turned cool. Because most of us "live in the moment" regarding weather, it seems now as though this cool weather will go on forever. It will not. The switch from much warmer than average to much cooler than average is something our weather does easily.
Although weather at our latitude most often comes from a westerly direction, the general west-to-east flow can be easily transported hundreds of miles north-to-south or south-to-north by a sudden shift in the Polar Jet Stream. This is precisely what has happened the past few days. This cooler weather will likely last, more or less, for a week or two, before warmer weather comes back north.