Was there mid June and the temps were 95-100 with 65% humidity. Rained a couple of the days in the afternoon.
French quarter is 7 short blocks away when you leave out the canal street exit door of the casino. Walk took me 20 minutes max. Early morning the temperature was no problem but coming back between 11-12 it was pretty sticky especially if there was no breeze.
An alternative is the streetcar/trolly that is located across the street (toward the river. It comes every 20 minutes and costs $1.25 (make sure you have exact change,) You can get an all day pass for $3.00.
My wife and I took the lunch cruise on the steamboat Natchez and I recommend it with the lunch. WIth AAA or AARP, you save a few bucks. Make sure and take a carraige ride around the French quarter. About $20 per perperson and had a great evening ride.
Ted in Chico