Ma'anar ƙamus na matsa lamba na yanayi shine ƙarfin da nauyin yanayin duniya ke yi akan raka'a na yanki a saman duniya. Matsi ne da ke haifar da nauyin iskar kwayoyin da ke cikin yanayin da ke sama da mu. Matsin yanayi a matakin teku an fi bayyana shi azaman 1013.25 millibars ko 1 yanayi (ATM). Matsin yanayi na iya bambanta da canje-canje a tsayi, zazzabi, da yanayin yanayi, kuma muhimmin abu ne a yawancin aikace-aikacen kimiyya da fasaha.