Virginia has quite a variation from north to south. Areas of northern Virginia, such as Dulles airport, have always been fairly close to NYC temperatures, at least in the colder months. The summer months down there are hotter.
Lets not forget the heat island affect, especially when it comes to night time temperatures. NYC has had a skyscraper boom in the past 10-15 years. That concrete simply does not allow the heat to escape at night.
So in 50 years the average dew point temperature at Islip has gone from 64 to about 66-67. It does look like we have been in a high trend for the past 9 years. Before 2010 it doesn't look like a big change.
I think Laguardia and Newark temperatures during heat waves are the highest around, especially night temperatures. They are open concrete and tarmac and Newark surrounded by chemical and industrial like plants. Kennedy not as bad because of the ocean and smaller airports are not surrounded by as much concrete.
Very slight west wind here, no sea breeze to be found. Yes the temperature has dropped from a high of 96 to 93 but that is only because of cloud cover.
It may not affect JFK as much but as NYC keeps growing with bigger and higher skyscrapers, I'm sure the maximum night temperatures will be higher. Heat island affect is so prevalent on nights like tonight.