Think 80F for the overnight low with 95% humidity, and you will be close.
Literally, you will be sticky, and sweaty, and wont be able to fall asleep till 1am when it finally cools off enough.
50F quilt is overkill. Try a sheet.
In a heat wave, it could be 90+ at midnight, with 100% humidity.
A cool front might bring mid 70s at night, best case.
Ive camped with it 85F and darn near 100% humidity at midnight ...in October