If it was 60 - 70 degrees, I would bet the farm on the Bears.
Again, it's been 20-25 degrees cooler in Chicago, and in Miami at 90 degrees the body does not have time to adapt when getting to Miami in mid week. Sure, they are pros, and will focus on hydration with appropriate salts and even IVs, but by the 4th quarter the Bears will slow down, not completely visible to the eye, a few will drop but the rest will just be a 1/3 step slower.
But by then Bears should have a nice lead, slow it down, run the clock.
I suggest everybody pass on this game.
(in the mid 80's when the Cards first moved to Phoenix, early season games outdoors were hilarious, Cards were so so but would come from behind 21 points to win in the 2nd half sometimes)