Why steam fog forms in the fall

In the coming months, early risers living near lakes, ponds or rivers will likely see steam fog which can make a beautiful sight in the early morning hours.

Less daylight and a lower sun angle during the fall months usually leads to cooler nights. During clear fall nights, the warmth from the land escapes into space and the air over land cools. However, since bodies of water such as ponds, rivers and lakes are much slower to cool than land, water surfaces are often warmer than the cooler land surfaces.

As the cooler air from land drifts over the warmer water, the rising water vapor from the warmer water condenses into droplets as it encounters the cooler air and forms fog. The fog is commonly seen as wisps of vapor emanating from the surface of the water.