My project investigates how the winter of 1708-09 became a standard of extreme cold in the collective memory of Europeans in the eighteenth century. I discern and trace three contemporary developments that contributed to the consolidation of this winter's reputation: meteorology, medicine, and frozen bodies of water. The advent of instrumental weather observation in the late seventeenth century engendered a new culture of quantifying the experience of cold and heat that did not exist in earlier meteorological traditions. I explore how the reporting of "record-low" temperatures measured by early thermometers caused both distress and curiosity across an expanding transnational public sphere of lay and learned readers in a period when thermometry was inaccurate and unstandardized. Moreover, I explore an unprecedented proliferation of theoretical writings on the nature and origins of cold in the aftermath. But thermometers alone cannot explain how 1709 became immortalized. Turning to the coastal cities of Marseille and Venice as case studies, I examine the frost's impact on their economies and how their citizens and correspondents abroad perceived the rare sight of frozen seas in warm climates. Finally, I turn to the medical dimension and the cost of human lives as a third contributing factor to the branding of Winter 1709. Alongside the large corpus of hospital and sanitation records, I focus on two doctors in Marseille and Venice, Charles de Peyssonnel and Bernardino Ramazzini, who wrote about the winter's effects on public health. I complete the triangle by studying Peyssonnel and Ramazzini's contributions to the ongoing scientific discussions of winter 1709 as extreme anomaly. In sum, I propose a cultural history of the making of a "Great Winter" by studying contemporary perceptions and attempts to orient their own experiences within the living memories and recorded histories of seasons.