Fish are cold blooded animals and as such their body temperature changes as the water surrounding them changes. Every species of fish has a water temperature that they are most comfortable in, meaning that their body functions properly at around that temperature. The comfort range for every fish varies around this absolute temperature and is normally expressed as a range of temperatures spanning from 10 to 15 degrees.
Remember that the temperature that boat equipment normally reads is the surface temperature and for every 10 feet of depth, there is a temperature drop of about 2 degrees.. If the weather continues to be hot, like it has been this year, the schools of bait fish that would normally hang around in small coves and channels, will also move into deep water because a couple degrees cooler water is very important to these small fish. If the bait schools go deep, the predator fish will follow. So on these hot days, fish deeper for more success.