"Okta" is the unit of measurement to describe the amount of cloud cover. Okta is reported in eighths of the celestial dome covered by all clouds visible. The codes represent: 0: 0/8, the complete absence of cloud; 1: 1/8 or less, but not zero; 2: 2/8; 3: 3/8; 4: 4/8, half of the sky is covered; 5: 5/8; 6: 6/8; 7: 7/8 or more, but not 8/8; 8: 8/8, sky is completely covered; 9: Sky obscured by fog and/or other meteorological phenomena; /: Cloud cover is indiscernible for reasons other than fog or other meteorological phenomena, or observation is not made.
Okta