Final answer:
Moist air cools more slowly than dry air due to lower evaporation rate on humid days and slower condensation process of water vapor in moist air.
Step-by-step explanation:
The reason why moist air cools more slowly than dry air is primarily due to the process of evaporation. On hot, dry days, the evaporation of sweat from the skin cools the body because the concentration of water in the atmosphere is lower, which increases the evaporation rate from the skin's surface. In contrast, on humid days, the concentration of water in the atmosphere is higher, which reduces the evaporation rate from the skin's surface, resulting in less cooling.
Additionally, evaporation plays a role in the cooling of the atmosphere as well. When moist air rises, it cools and its water vapor condenses, leading to precipitation. This cooling effect is more pronounced with moist air because the water vapor in the air needs to release its latent heat of vaporization to condense, which slows down the cooling process.
In summary, the higher concentration of water in the atmosphere on humid days reduces the evaporation rate from the skin's surface, and the condensation of water vapor in moist air releases latent heat, both of which contribute to the slower cooling of moist air compared to dry air.