What causes the air above land to cool at night compared to the air over water?

The reason the air above land cools at night more significantly than the air over water relates to the differing thermal properties of land and water. Land has a lower heat capacity than water, which means it doesn't retain heat as effectively. After sunset, the land surfaces lose heat quickly because they have absorbed solar energy during the day and release it more rapidly at night.

In contrast, water has a high heat capacity, which allows it to maintain heat for longer periods. It takes more energy to change the temperature of water compared to an equal area of land. Thus, the air above water tends to remain warmer due to the slower cooling of the water itself.

This phenomenon is crucial in meteorology and affects local weather patterns, often resulting in cooler temperatures over land during the night compared to adjacent bodies of water.