According to this website: 
http://www.getsomebass.com/largemouthbass_bio.html
It says for the Northern Strain: "Typically 75-85 degrees is their “perfect” temperature. When the  shallows get too warm, during the dog days of summer, largemouth will  tend to head to slightly deeper water to stay in their comfort zone.  This is especially true of the biggest fish. This establishes the  stopping point of their migrations to the shallows."
For the Florida Strain: [FONT=Arial, Helvetica, sans-serif]
               Also, they can tolerate a wide range of water clarities  and bottom                types, prefer water temperatures from 65 to 85 degrees,  and are                usually found at depths less than 20 feet. [/FONT]
This site 
http://www.bassfishingandcatching.com/largemouth-bass-habitat.html says that "They function best in water between 65° and 90°F, but they are able to  tolerate water that rises to the 
"low 90s" in the southern  states."
[FONT=Arial, Helvetica, sans-serif]
http://www.warmwaterflyfisher.com/WWspecies/bigsunfish.htm
Habitat:                 The largemouth is the classic"warm-water" species.                It flourishes in waters warmer than 80 degrees and can  survive temperatures                in the mid-90's.[/FONT]
There are numerous sites that give the same info.
 My temp is currently at 80 degrees. I think YOU should do YOUR research before opening YOUR mouth.