Swiss-born American geologist, geographer, and educator whose extensive meteorological observations led to the founding of the U.S. Weather Bureau. The guyot, a flat-topped volcanic peak rising from the ocean floor, is named after him.

He studied at the College of Neuchâtel and in Germany, taught at Paris from 1835 to 1840, and became professor of history and physical geography at the Neuchâtel Academy in 1839. In 1838, under the influence of the famed naturalist-geologist Louis Agassiz, he took up the study of the structure and motion of glaciers.

In 1848 Guyot settled in Cambridge, Mass., and until 1854 lectured on geography and teaching methods for the Massachusetts Board of Education. He wrote a series of geography textbooks that served as models of the kind used in American schools for many years. In 1854 he became professor of geology and physical geography at Princeton University. Guyot developed topographical maps of the Appalachian and Catskill mountains. His published works include The Earth and Man (Eng. trans., 1849); Creation, or the Biblical Cosmogony in the Light of Modern Science (1884); and Tables, Meteorological and Physical (4th ed., 1887).