WHY THE WATER IN AN EARTHEN POT IS COOLER THAN THE WATER IN A METALIC JUG OR A GLASS TUMBLER?

If you observe an earthen pot closely,you will notice many tiny little holes on its surface(you can use a magnifying glass).When water is kept in such an unglazed earthen pot it comes out slowly onto the outer surface seeping through the pores in the pot.Then evaporates taking away some amount of heat from the vessel and its contents.This is the heat required to change a substance from its liquid state to vapour.The degree of cooling of the contents varies with the environment.On a hot dry day the evaporation is faster and the cooling effect is greater.The evaporation is aided by breeze and the stronger it blows the faster is the evaporation (you will notice a similar effect if you are wet and stand under a fan)