lake effect

n.
The effect of any lake, especially the Great Lakes, in modifying the weather in nearby areas.

A term used by growers around the Great Lakes area and other large lakes in colder regions to describe the environmental influence such lakes have on growing patterns. As the spring growing season for grapevines begins, the lakes' cooling effect (stored from the winter) retards the vines from budding until the spring frost season is over. The lakes store daytime heat as the growing season continues. The effect of the warming water lessens the variation between day and night temperatures, which lengthens the growing season (compared to nearby areas) by as much as four weeks. As summer draws to an end, the stored warmth of the lakes delays frost that might damage vineyards in the fall. In winter, the lakes also cause heavy, moist snowfall, which blankets the vineyards, insulating and protecting the vines from the frigid air. The Lake Effect influences the environment for about 20 to 25 miles inland from the shore, creating a positive viticultural environment that wouldn't exist otherwise in the northern climes. It allows states like michigan, new york, pennsylvania and ohio to grow grape varieties that have trouble surviving further south in states like missouri. It is this same effect that allows the finger lakes ava in New York to provide a hospitable environment for viticulture.