Snow cover and duration are very variable components of the alpine environment and are often poorly reproduced in climate models. Using joint probability temperature/precipitation distributions to categorize cold/dry, cold/moist, warm/dry (WD) and warm/moist situations in winter, this study demonstrates that one particular mode (WD) exerts the strongest influence on snow. When the number of WD days is low, snow in the Swiss Alps is abundant, and vice versa. Since the 1950s, there has been an increase in the WD events and a subsequent reduction in snow cover. Snow-abundant winters have nevertheless occurred in recent years, when WD days are low, despite winter temperatures that are more than 1 °C higher than those in the mid-1900s. The WD mode thus represents a form of proxy to snow amount and duration; its evolution in an enhanced greenhouse climate can help identify whether snow-abundant winters may still occur in a much warmer world.