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Heat is necessary to produce Yellowstone’s geysers and hot springs, but this ingredient doesn’t come from the climate! The average annual temperature of Yellowstone is only 36°F (2.2°C). On many winter days, the air temperature hovers well below freezing.

Rather, an enormous amount of heat comes through the ground. It is estimated that the temperature in the underlying magma chamber at Yellowstone may exceed 1,475 °F or 800°C.

The average amount of heat that is transmitted from the interior of the Earth to its surface is 30-40 times greater in the Yellowstone area than in other places on Earth’s continents. About 25 percent of this heat is released by conduction, while the other 75 percent is released by convection.

Scientists of the Yellowstone Volcano Observatory compare the magma chamber to a water-filled sponge: the sponge represents the solid rock, whereas the water represents the molten areas. The magma body beneath Yellowstone consists of approximately 90 percent solid rock interspersed with 10 percent molten rock.

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