Octa vs. Okta — What's the Difference?

(meteorology) The proportion of the sky that is obscured by clouds, in eighths (one octa means that one eighth of the sky is obscured, two octas that one quarter is obscured, and so on).

In meteorology, an okta is a unit of measurement used to describe the amount of cloud cover at any given location such as a weather station. Sky conditions are estimated in terms of how many eighths of the sky are covered in cloud, ranging from 0 oktas (completely clear sky) through to 8 oktas (completely overcast).

(meteorology) One eighth of the total area of the celestial dome; used as a measure of cloudiness (one okta means that one eighth of the sky is obscured, two oktas that one quarter is obscured, and so on).