Dew forms under which conditions?

Dew forms under which conditions?

• A. Clear Skies, High Relative Humidity, and No Wind
• B. Overcast Skies and Strong Winds
• C. Hot, Dry Conditions
• D. Rainy Conditions

Answer: (A)

Dew forms when the surface cools to the air’s dew point, causing water vapor to condense on surfaces. This happens best under clear skies at night because radiative cooling from the ground is unimpeded, allowing the surface temperature to drop. A high relative humidity means there’s enough water vapor present to condense, and light or no wind keeps the cool air near the surface from being mixed away or evaporated, so condensation can occur on surfaces. Other conditions hinder dew formation: cloud cover traps heat and reduces radiative cooling, making the surface stay warmer; strong winds mix and disrupt the cool, near-surface layer; hot, dry conditions have little moisture to condense; rainy conditions bring clouds and precipitation that also suppress the necessary radiative cooling.

Dew forms when the surface cools to the air’s dew point, causing water vapor to condense on surfaces. This happens best under clear skies at night because radiative cooling from the ground is unimpeded, allowing the surface temperature to drop. A high relative humidity means there’s enough water vapor present to condense, and light or no wind keeps the cool air near the surface from being mixed away or evaporated, so condensation can occur on surfaces. Other conditions hinder dew formation: cloud cover traps heat and reduces radiative cooling, making the surface stay warmer; strong winds mix and disrupt the cool, near-surface layer; hot, dry conditions have little moisture to condense; rainy conditions bring clouds and precipitation that also suppress the necessary radiative cooling.