Even if the temp sticks at 99, this is a borderline historic day. A 99/83 is a 91.0 average, which looks like a top-15 all-time day.
(caveats - if we snuck a 99 in there, and if it doesn't storm)
I don’t trust many PWSs other than my own, but there are a bunch of them at or above 100 near BWI. If we had avoided the clouds in DC we might have been able to make a run.