When do clouds, fog, or dew form?

Clouds, fog, and dew form as a result of water vapor condensing in the atmosphere. This process occurs when the air becomes saturated with moisture to the point where it can no longer hold all of the water vapor in the gaseous state. As the temperature of the air drops or when it reaches a certain pressure, the water vapor transitions into tiny water droplets or ice crystals, creating visible clouds or fog. Dew is formed when the temperature of surfaces drops at night, cool enough for the moisture in the air to condense into liquid droplets.

While other factors such as atmospheric pressure, temperature, and humidity can influence the conditions that lead to condensation, the direct mechanism that leads to the formation of clouds, fog, or dew is the process of water vapor condensing. This highlights the importance of understanding the role of condensation in meteorological phenomena.