Yankuna masu zafi wato Tropics sune yankin Duniya da ke kewaye da tsakiyar duniya - Equator. Tropic of Cancer a Arewacin Hemisphere yana iyakance su a cikin latitude 23°26′11.3″ (ko kuma 23.43649 °) N da Tropic na Capricorn a Kudancin Hemisphere a 23°26′11.3″ (ko kuma 23.43649 °) S; waɗannan latitude sun yi daidai da karkatar da duniya. Har ila yau ana kiran wurare masu zafi da wurare masu zafi da yankin torrid (duba yankin ƙasa ). Yankunan zafi sun haɗa da ko'ina a Duniya wanda ke ƙarƙashin ƙasa ( Rana tana saman kai tsaye ) aƙalla sau ɗaya a cikin shekarar hasken rana . Don haka matsakaicin latitudes na wurare masu zafi suna da ƙima iri ɗaya mai kyau da mara kyau. Hakanan, suna kimantawa, saboda ƙasa ba cikakkiyar madaidaiciya ba ce, “kusurwar” karkatacciyar ƙasa . Ita kanta "kusurwar" ba a daidaita ta musamman saboda tasirin wata, amma iyakokin wurare masu zafi shine babban taron ƙasa, kasancewa matsakaicin tsari, kuma bambancin ƙarami ne. Dangane da yanayi na klimate, wurare masu zafi suna samun hasken rana wanda ya fi sauran Duniya kai tsaye kuma galibi suna da zafi da ɗumi.