The leaf of the plants are heated by the temperature of the environment and also by the heat released during photosynthesis. Thus, transpiration provides a cooling mechanism for the plant to release excess heat in the leaves in order to maintain internal temperature necessary for biological and chemical processes. Transpiration tends to occur more quickly at higher temperatures i.e., in sunny days due to increased evaporation. And on windy days'the moisture present in the air is swept away from the leaf causing it to transpire more. Whereas on cool and calm days, the humidity rate can rise which intum causes a decrease in transpiration.