Basking in the sun is important for absorbing solar
energy and raising body temperature. This helps a frog
have a temperature higher then it's environment.
The Andaean Toad, Bufo spinulosus, has been know to
raise it's temperature to 15°C above air temperature
in the shade.
Increased body temperature accelerates growth, digestion
and produces fat deposits.
Frogs tend to bask in moist area so not too much water