ArgumentWhat, if anything, uniquely defines the mountain as a “laboratory of nature”? Here, this question is considered from the perspective of meteorology. Mountains played a central role in the early history of modern meteorology. The first permanent year-round high-altitude weather stations were built in the 1880s but largely fell out of use by the turn of the twentieth century, not to be revived until the 1930s. This paper considers the unlikely survival of the Sonnblick observatory (3105 m.) in the Austrian Alps. By examining the arguments of the Sonnblick’s critics and defenders, it reveals a seemingly paradoxical definition of the mountain as a space that simultaneously maximized isolation and communication. Drawing on the social and environmental history of the Alps, it shows how the Sonnblick came to appear as the perfect embodiment of this paradox. . Mountains have played a central role in the history of meteorology, particularly in the infant discipline’s “discovery of the third dimension” in the last third of the nineteenth century. From the 1860s, meteorologists began to recognize that the vertical structure oft he atmosphere held vital clues to large-scale weather trends. They began to distinguish between ground-based measurements, which reflected local peculiarities influenced by land forms and water, and measurements taken at high altitudes, which revealed general characteristics of the atmospheric circulation. The meteorological study of the upper atmosphere intensified in the 1880s with the construction of the first permanent yearround high-altitude weather stations.1 Yet this trend proved short lived. By the 1890s, most meteorologists studying the upper atmosphere were trading their hiking boots for a new generation of unmanned kites and balloons. By the turn of the twentieth century, most mountain-top weather stations had fallen out of use – not to be revived until the 1930s, when the aviation industry generated a new demand for their data. Yet one observatory survived this crisis against overwhelming odds.