It’s no fun in spring to be “cooler along the lake” so I’m curious if there’s a benefit on the flip side in the autumn that we’re “warmer along the lake?”
—James Puricelli Evanston
There sure is. Lake Michigan is Chicago’s natural air conditioner in spring and summer, but often warms areas near the lake in fall and winter. Water has a high specific heat, making it slow to warm in spring and slow to cool in fall. On warm days when winds are light, the heated air over the land rises, allowing the cooler and denser air over the lake to flow onshore, delivering a cooling lake breeze. During the cold season, when the lake is warmer than the air, onshore winds deliver that warmth inland. In late fall or early winter, this lake-enhanced warming can cause it to rain near the lake, while snow is falling inland.