Which best describes what happens between mountains and valleys during the summer months at night?

During the summer months at night, valleys tend to cool down more rapidly than the surrounding mountains due to their lower elevation and the accumulation of cold air. This phenomenon results in cold air drainage, where cooler, denser air flows down from the mountains into the valleys. As a consequence, valleys can experience significantly lower temperatures compared to the mountains, creating a distinct temperature gradient between the two. This process can influence local weather patterns and ecosystems.