Wet clothes dissipate heat much faster than dry clothes due to a phenomenon called "evaporative cooling." When water evaporates from the surface of wet clothes, it absorbs heat energy from the fabric, causing it to cool down. This process happens because the molecules of water gain enough energy to break free from the liquid state and become water vapor.
The evaporation process requires energy, and this energy is taken from the surrounding environment, including the fabric of the wet clothes. As a result, the fabric loses heat to the evaporating water molecules, causing it to cool down more rapidly than if it were dry.
On the other hand, dry clothes do not have water on their surface that can readily evaporate, so there is no significant heat loss through evaporative cooling. The absence of water molecules evaporating from the fabric means that the heat energy remains trapped within the material, keeping the clothes relatively warmer.
This evaporation-driven cooling effect is why wet clothes can feel significantly colder on the skin compared to dry clothes, especially in windy or low-humidity conditions where evaporation happens more quickly. It's also why wearing wet clothes in cold weather can be dangerous, as the body can lose heat rapidly, increasing the risk of hypothermia.