Sky's the Limit: Ace Your AMS Certification Test 2026 – Become a Weather Wizard!

Fog typically forms under conditions of low temperatures and high humidity. This combination allows the air to become saturated with moisture, leading to the condensation of water vapor into tiny water droplets suspended in the air, which we perceive as fog.

When temperatures are low, the air can hold less moisture before reaching saturation. Therefore, at high humidity, even a slight drop in temperature can lead to the air reaching its dew point, resulting in the formation of fog. This is especially common in the early morning or late evening when temperatures drop and humidity levels often peak.

In contrast, conditions like high wind speeds tend to disperse moisture and prevent fog formation. High temperatures also decrease relative humidity and increase evaporation, making it less likely for fog to form. Extreme precipitation can create conditions favorable for fog in its aftermath, but it is not a direct cause. The presence of low temperatures combined with high humidity is the primary and essential factor in fog formation.