When cold air is at the top of mountains the air during the night will do what?

When cold air is at the top of mountains during the night, it tends to sink down the slopes due to its higher density. This process, known as cold air drainage, results in cooler temperatures in the valleys below as the cold air settles there. Consequently, valley areas can experience significantly lower temperatures compared to the mountain tops. This phenomenon is often more pronounced on clear, calm nights.