there was one summer day in the middle of the 2010s - I don't know if you all remember it, but the mid atlantic and NE had INSANELY high dewpoints. I think Dover, DE was up in the mid 80s. I'm pretty sure both Central Park and DCA cracked 80F. JFK had an hourly ob with a dewpoint of 84F lol. That day was probably my max - I just remember any aerobic activity outside being a real struggle.
There was another afternoon when we had just moved to DC and a t-storm was passing just to our north. It was far enough away to keep our air temp in the mid 90s but it pushed the dewpoint up to around 84 (per my local weather station). I was running at the time and that was not easy.