My daughter and I got to Toy Story parking around 3:30 and it was dead. Got into the parks and while there were people around, wait times were low, FPs for almost everything were immediate - Clarabelle’s ice cream was a walk-up even in the oppressive heat.
By 5:00, there were more people around and wait times crept up a bit. There was like a 5-minute line to get into DCA.
My husband Ubered over around 7 and said it still seemed dead getting into DL, but he wasn’t trying to deal with parking.
By 7, front row Main Street parade spots were gone, and there wasn’t a whole lot left in general. It was pretty nuts, the busiest I’ve seen the parade viewing in a long time (I wasn’t there for opening day of MSEP this year, but I was there on the second day, a Saturday - this was worse).
By fireworks time, as the photo I posted above indicates, it was a PACKED sea of humanity. They had good crowd control for it, though; they were ready for the crowds.
Other things with long lines all day: popcorn buckets and characters in Halloween costumes.
It was So. Hot. But a great day!