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How Hot is Old Faithful?

a late evening eruption of Old Faithful as seen through a red fliter

• Deep within the plumbing system of Old Faithful, water temperatures exceed 400°F (204°C).

• At only 45 feet (14 m) inside Old Faithful’s throat, the water temperature is 244°F (117°C).

• Prior to an eruption, the water at the geyser’s vent is 204°F (96°C)—several degrees hotter than the area’s normal surface boiling point of 199°F (93°C).

Although Old Faithful is world famous, it is only one of more than 12,000 hydrothermal features in Yellowstone and represents only a tiny fraction of the area’s thermal output.

Next Section: Norris Geyser Basin

drawing of the OFVEC
Young Scientists
Yellowstone Express
Why Geysers Erupt
Hot Water Treasures
Hot Spring Ecology
Scientific Research

This work is supported by

National Science Foundation    Yellowstone Park Foundation

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