Dear Tom,
I have visited many caves across the U.S. I notice the temperature is around 55-56 degrees. Do most caves around the world fall in this range?
— Michael O’Brien, Chicago
Dear Michael,
There is variability in cave temperatures worldwide. Several factors influence cave temps. Chief among these are temperature of overlying rock and heating from below. The ground is a good thermal insulator. Seasonal change in surface temperature is typically noticed only to a depth of about 50 feet. So, cave temps mirror the average annual temperature of the surface, which in turn is dictated largely by altitude and latitude. In the continental U.S., 55-56 degrees is close to normal. Caves also are heated from below. Caves away from tectonic activity receive little heat from below, while areas where magma lies closer to the surface, such as Yellowstone National Park, can be much warmer than average surface readings.
