Izimo zenyanga
Izimo zenyanga ziyizimo ezibonakalayo zosuku nobusuku enyangeni njengoba zibukelwa kude. Ngenxa yokuthi inyanga ivaliwe eMhlabeni, umjikelezo wezimo zenyanga uthatha inyanga eyodwa futhi wenzeka ohlangothini olufanayo lwenyanga, oluhlale lubhekene noMhlaba. Ngokwenkulumo evamile, izimo ezine zenyanga eziyinhloko ziyisitime, isihhemu, ukudilingana kanye nesicheme; izimo ezine ezincane yisidengele, isidilingana, ithwasa, kanye nenhlendla iyemuka. Inyanga ephelele iyisikhathi esiphakathi kwesitime kuya kwesinye isitime : ngenxa yobukhophelana bozungezo lwenyanga, lesi sikhathi siyaguquguquka futhi silinganiselwa ezinsukwini ezingaba ngama-29.5.
Ummom wenyanga (isimo sayo) uyaguquka kancane kancane ngenyanga eyodwa njengoba izikhundla ezicakathayo zozungezo lwenyanga lapho izungeza uMhlaba, kanye noMhlaba ozungeza ilanga, ziguquka. Uhlangothi olubonakalayo lwenyanga lukhanyiswe ilanga ngamazinga ahlukile, kuye ngesikhundla senyanga ozungezweni lwayo, kanye nengxenye ekhanyiswe yilanga ehlukahluka kusuka ku-0% (makuyisitime) kuya cishe ku-100% (mayidilungene).