Principle 3

The Great Lakes influence local and regional weather and climate.

A:
The Great Lakes affect weather and climate by impacting the basin’s energy and water cycles. Changes in the Great Lakes’ water circulation, water temperatures and ice cover can produce changes in weather patterns.
B:
The Great Lakes warm by absorbing solar radiation. Lake temperatures are also affected locally by the temperature of inflowing river waters. The Great Lakes lose heat by evaporation and by warming the overlying air when the atmosphere is cool. After water vapor is released into the atmosphere, it condenses and forms precipitation, some of which falls within the Great Lakes Basin.
C:
The Great Lakes modify the local weather and climate. Because water temperatures change more slowly than land temperatures, lake waters gain heat in summer and release heat during cooler months. This results in cooler springs, warmer falls, delayed frosts and lake effect snow.
D:
The Great Lakes have a significant influence on regional climate by absorbing, storing and moving heat and water. Lake effect precipitation can occur downwind when major weather systems move over the lakes.
E:
The Great Lakes are influenced by larger climate change patterns affecting North America and the world. Climate patterns in the Great Lakes are changing, with warmer and drier conditions predicted.