Based on official NWS Climate Sites in most cases, daily climate reports and NOWData tabs on the NWS websites. Should be considered unofficial until NWS issues record reports on them. Feel free to post any corrections/additions.
Best of the best
Newark, NJ 108 (All-time record)
Hartford, CT (Bradley) 103 (All-time record)
Washington, DC (Dulles) 105 (All-time record)
Salisbury, MD 102 (Unofficially ties all-time record)
Trenton, NJ 106 (Ties all-time record)
Bridgeport, CT 103 (Ties all-time record)
Best of the Rest
Portland, ME 100 (Daily record, #4 all-time)
Concord, NH 100 (Daily record)
Boston, MA 103 (Daily record, #2 all-time)
Providence, RI 101 (Daily record, #4 all-time)
Islip, NY (Long Isl) 100 (Daily record, #4 all-time)
New York City (Central Park) 104 (Daily record, #4 all-time)
New York City (JFK Airport) 103 (Daily record, #2 all-time)
New York City (LaGuardia Airport) 103 (Daily record (#3 all-time)
Scranton, PA 98 (Daily record)
Williamsport, PA 103 (Daily record, #4 all-time)
Atlantic City, NJ (Pomona) 105 (Daily record, #2 all-time)
Allentown, PA 104 (Daily record, #2 all-time)
Philadelphia, PA 103 (Daily record, #4 all-time)
Wilmington, DE 102 (Daily record #7 all-time)
Harrisburg, PA 103 (Daily record, #7 all-time)
Baltimore, MD (BWI Airport) 106 (Daily record, #2 all-time)
Baltimore, MD (Inner Harbor) 108 (Not an official record, but impressive)
Washington, DC (Reagan National) 102 (Not a record)
Wallops Island, VA 100 (Daily record, #3 all-time)
Norfolk, VA 102 (Daily record, #9 all-time)
A few notes about the heat. I think you can thank overnight low temps for this…temps started off incredibly warm this morning, with many areas not getting below 80 degrees. That helped lead to a very rapid warm up during the climatological hottest time of the year. This was essentially a perfect storm of heat…an anomalously strong mid-summer ridge building into areas during the peak temperatures of the year. Timing is everything, and this was timed out rather well (or probably not if you are sick of the heat already). Was it because of global warming? The answer I want to give is “no,” but the answer that is correct is that we simply do not know. Singular events are impossible to link to a warming planet because of greenhouse gases. Singular events should NOT be used as proof one way or another regarding global warming. It takes years of trends to prove the argument one way or another, and one day we’ll figure that out. For now, just accept that it’s summer and it’s hot, and try and keep cool the best you can.
One more day of excessive heat tomorrow, though I believe thunderstorms will be more scattered about, so that will help the situation some. After a cooling trend early next week, we look to see impressive, significantly hot temperatures return late next week and weekend. Though likely not quite as bad as today, there’s a lot of potential then as well to be record breaking type heat, but more on the low scale…not the all-time stuff. I sincerely believe we will see at least 1-2 more blasts of substantial heat (stronger than the usual stuff) through August before this summer starts to loosen its grip. So stay ready to keep cool!
State of Occlusion 
Crazy. Thanks for compiling. I love looking at weather records.