Under what conditions do clouds typically form?

Clouds typically form when there is enough moisture present in the air, and the temperature drops to the dew point. The dew point is the temperature at which the air becomes saturated with moisture, leading to condensation. When air cools, its capacity to hold water vapor decreases, and if the air cools to the dew point, the water vapor condenses into tiny water droplets or ice crystals, depending on the temperature. This process creates clouds.

The other options consider conditions that may or may not contribute to cloud formation but do not directly address the necessary relationship between moisture and temperature. For example, while freezing temperatures can lead to cloud formation when moisture is present, it is not a primary condition for clouds to form. Similarly, wind can influence cloud movement but does not determine whether clouds will form. The time of day, such as sunset, can affect temperature and humidity but is not a direct cause of cloud formation.