The Great Lakes Frozen, Canada–United States Border, North America

The Great Lakes have a humid continental climate, Köppen climate classification Dfa (in southern areas) and Dfb (in northern parts) with varying influences from air masses from other regions including dry, cold Arctic systems, mild Pacific air masses from the West, and warm, wet tropical systems from the south and the Gulf of Mexico. The lakes themselves also have a moderating impact on the climate, they can also increase precipitation totals and produce lake-effect snowfall.
• Lake effect
The most well known winter effect of the Great Lakes on weather there is the lake effect, sometimes very localized. Even late in winter lakes often have no icepack in the middle. The prevailing winds from the west pick up the slightly warmer air and moisture from the lake surface, in relation to the cold surface winds above. As the slightly warmer, moist air passes over the colder land surface, the moisture often produces concentrated, heavy snowfall that sets up in bands or "streamers". This is similar to the effect of warmer air dropping snow as it passes over mountain ranges. During freezing weather with high winds, the "snow belts" receive regular snow fall from this localized weather pattern, especially along its eastern shore. Snow belts are found in Wisconsin, Michigan, Ohio, Pennsylvania, Ontario, and New York.
The lakes also moderate seasonal temperatures to some degree but not as large an influence as do large oceans, by absorbing heat and cooling the air in summer, then slowly radiating that heat in autumn. They protect against frost during the transitional weather, but they also keep the summer time temperatures cooler than further inland, but this effect can be very localized and overridden by offshore wind patterns. This temperature buffering produces areas known as "fruit belts", where fruit typically grown much farther south can be produced. Western Michigan has apple and cherry orchards, and vineyards adjacent to the lake shore as far north as the Grand Traverse Bay and Nottawasaga Bay in central Ontario. The eastern shore of Lake Michigan and the southern shore of Lake Erie have many wineries as a result of this, as does the Niagara Peninsula between Lake Erie and Lake Ontario. A similar phenomenon allows wineries to flourish in the Finger Lakes region of New York as well as Prince Edward County, Ontario on Lake Ontario's northeast shore. Related to the lake effect is the occurrence of fog over medium-sized areas, particularly along the shorelines of the lakes. This is most noticeable along Lake Superior's shores.