A good delimiter for big-time heat years is whether there are 20 or more 95+ days. There have only been 12 of those in DCA history (2016 being the latest, 2012 having the record of 29). We are currently sitting at 10 with plenty more to come. If you do year-to-date, 2024 only trails:
2012 (14)
2010 (11)
1991 (13)
1911 (11)
Interestingly, in 2016 the heat was backloaded, with only 1 95+ day through 7/9, on the way to 23 total.