Why are earthen pots wrapped with a wet cloth during summers?

Answer 1

To prevent cracking of the pots from too rapid dehydration.

In a hot environment clay pots will lose surface moisture at a higher rate than the interior of the pots walls will. Clay shrinks as it dries, if the outside dries faster than the interior of the clay walls you will have cracks form. To reduce the likelihood of this occuring, pottery is often kept either wrapped in plastic or covered with a wet cloth to retard rapid dehydration.

Basically, you want to keep the moisture throughout the walls of a pot at a somewhat uniform level, the wet cloth assists this.

Answer 2

Wrapping earthen pots with a wet cloth during summers helps to keep the water inside cool by promoting evaporation. As the water evaporates from the cloth, it draws heat from the pot, thus maintaining a lower temperature inside. This process helps to keep water or other substances stored in the earthen pots cool and refreshing during hot weather.