total cloud amount
fractional cloud cover
Note 1 to entry: Observation of total cloud amount is usually recorded in tenths or oktas, where one okta indicates an extent of cloud cover equal to one eighth of the sky.
Note 2 to entry: The total cloud amount has unit one.
Note 3 to entry: This entry was numbered 845-09-92 in IEC 60050-845:1987.
Note 4 to entry: This entry was numbered 17-1321 in CIE S 017:2011.