Explain why malaria is restricted to the tropics?

Plasmodium falciparum is the causative agent of the most severe form of malaria. It is distributed throughout the tropics. Explain why malaria is restricted to the tropics?

Malaria is transmitted by Anopheles mosquito, which is insect vector for the Plasmodium falciparum parasite.
This parasite needs warm conditions with temperatures above 20°C to complete its life cycle in the mosquito. Therefore, mosquitoes breed in warm conditions of tropics and in areas of stagnant water.