Final answer:
Draught or wind increases evaporation by reducing local humidity and allowing for a greater vapor pressure difference between the evaporating surface and the air, which leads to faster water loss from surfaces like leaves or skin.
Step-by-step explanation:
Having a draught or wind can increase the rate of evaporation by replacing the air that is already saturated with water vapor with drier air, allowing more water to evaporate. This phenomenon is because evaporation depends partly on the vapor pressure difference between the evaporating surface (like a leaf or skin) and the air. If the surrounding air is humid, the difference in vapor pressure is low, thus reducing evaporation rates. Conversely, wind decreases the surrounding air's humidity by moving the humid air away and bringing in drier air, which increases the vapor pressure difference and, therefore, enhances evaporation. Adding wind to an environment, therefore, can significantly increase the rate at which moisture evaporates.
For example, plants and fungi need to balance their temperature and water retention, and wind can affect this by increasing water loss from leaves through evaporation. Similarly, the evaporation of sweat from the human skin is the primary means of cooling the body during exercise, and this process is more effective in windy conditions due to the lower relative humidity near the skin surface enabled by the moving air.