why does a desert cooler cool better on a hot dry day

A desert cooler cools better on a hot dry day because it works on the principle of evaporation, which is more effective under conditions of high temperature and low humidity. On a hot day, the air's ability to absorb moisture increases, so when the cooler passes hot air over water-saturated pads, the water evaporates faster. This evaporation process absorbs heat from the air, cooling it down. When the air is dry, there is less moisture in the atmosphere, allowing more water from the cooler to evaporate, thus enhancing the cooling effect. Therefore, a hot, dry day with low humidity creates the perfect environment for a desert cooler to work efficiently, providing a significant drop in air temperature and comfortable cooling.