Yanayi shine matsakaicin yanayi na yau da kullun, wanda aka saba da shi tsawon shekaru 30. Ƙari da ƙarfi, shine ma'anar da canjin yanayin canjin yanayi a tsawon lokacin da ya fara daga watanni zuwa miliyoyin shekaru. Wasu daga cikin canjin yanayi da ake yawan aunawa sune zazzabi, zafi, matsin yanayi, iska, da hazo . A taƙaice, yanayi shi ne yanayin abubuwan da tsarin tsarin yanayi ya ƙunsa, wanda ya haɗa da teku, ƙasa, da kankara a doron ƙasa. Yanayin wani wuri yana shafar latitude / longitude, ƙasa, da tsayin sa, da kuma ruwayen ruwa da ke kusa da su. Za'a iya rarrabe yanayi gwargwadon matsakaita da matsakaicin jeri na masu canji daban -daban, galibi yawan zafin jiki da hazo. Tsarin rarrabuwa da aka fi amfani da shi shine rarrabewar yanayi na Köppen. Paleoclimatology shine nazarin tsoffin yanayi. Tun da akwai 'yan kallon kai tsaye na yanayin ƙasa kafin ƙarni na 19, ana samun paleoclimates daga masu canza wakili waɗanda suka haɗa da shaidar ba-biotic kamar ɓoyayyen da ake samu a cikin gadajen tafki da kankara, da kuma shaidar halittu kamar zoben itace da murjani.