In fact, on July 20, 1977, 0.06" rain fell. July 21, 1977 saw the mercury hit 104°.
I always wondered how NYC hit 104 that day, because the park had actually cooled down after a 2 day streak of 100+ and then got even hotter the day after it rained! If that rain hadn't occurred, the park would have had 4 straight days of 100+!!!!
That day it didn't hit 100 and it rained, was that the day of the big blackout Don or did that happen before?