What factors contribute to the formation of fog?

Fog formation is primarily influenced by a combination of environmental conditions that lead to the cooling of air and an increase in humidity. High humidity is crucial because it indicates that the air is saturated with moisture. When humidity reaches critical levels, the air can no longer hold additional water vapor, which can lead to the condensation of water vapor into tiny droplets that form fog.

Light winds play a supportive role by allowing the moist air to remain close to the ground without dispersing too quickly. If the winds were too strong, they would promote mixing and disrupt the calm conditions necessary for fog to coalesce. Cool temperatures also contribute significantly because they can lower the air's capacity to hold moisture, thereby facilitating the condensation process.

In contrast, the other factors listed in the options do not favor fog development. High temperatures and strong winds can lead to evaporation and dry air conditions, which typically inhibit fog formation. Heavy rainfall and thunderstorms can sometimes lead to temporary fog conditions post-rain; however, they do not create ideal static conditions for fog to persist. Extreme cold and clear skies usually lead to ice formation but do not create the necessary moisture conditions for fog. Therefore, the combination of high humidity, light winds, and cool temperatures is essential for fog to form, making the first