91Ó°ÊÓ

Two climates, a hot, humid day and a hot, dry day in the desert, are given.

The relative humidity depends on the amount of vapor that is in the air. For tropical regions, on a hot, humid day, the air already has enough content of water in it. In the desertic climate, the air is dry, and the temperature of the atmosphere also supports the evaporation of the water from water bodies or sources.

The answer is that high humidity makes it difficult to shed excess body heat with the help of sweat, or what we call the evaporation process. When sweat droplets come out of pores, and the hot temperature of the atmosphere converts them into vapor, it helps out the skin to cool down with this process.

In humid tropical areas, there is no space left for new water droplets to join in the air, so it prevents evaporation as compared to the dry, hot area of a desert where it supports the same process.

Thus, we generally feel more uncomfortable on a hot, humid day in the tropics than on a hot, dry day in the desert.