The average air temperature of a cave depends entirely on its location. Generally, the temperature of a cave is approximately the average annual surface temperature of the region In which it is located.
The Carlsbad Caverns in northern Texas, for example, have an average air temperature inside the caves of 70 degrees, while the mean surface temperature of the area is 63 degrees. Crystal Cave, located in western Wisconsin, has an average cave air temperature of 49 to 50 degrees, also close to the average annual surface temperature of its region. Cave temperatures generally change very slowly, except where large entrances allow outside air to change significantly the interior air temperature.