No they do not cancel the performances
Went on the 26th. 100+ during the day, but 80 in the evening and 70 by the end of the show. It was just fine.
Went there on the 21st sound of the music show. Day the was in the 95 degrees, by the time show start temperature dropped to 7x degree, and at it end it was almost a little chilly with the wind.
Thanks! Your answer is awaiting moderation.