With a 1am temp of 85F, June 23 goes in the books for DCA as:
High: 99F
Low: 81F
This is the earliest reading above 80F on record at DCA and only one of a handful of times of an 80+ low in June. This is the first 80+ low at DCA since 2019.
BWI also records a low of 81F for yesterday (98/81) - not sure on records there but I can't imagine many other June nights this warm.