Cloud cover converter
Convert how much of the sky is covered between oktas, percent and tenths, with the code aviation weather reports use.
That is 4 oktas: reported as SCT (scattered).
What it means
How cloudy is that?
Observers estimate cover by eye or with a ceilometer; 0 oktas is clear, 8 overcast, and 9 means the sky cannot be seen (fog).
Every unit
That sky in every unit
Learn
Three things worth knowing
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12.5 % an okta
Each okta is an eighth of the sky: 2 oktas is 25 %, 6 oktas 75 %.
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Eighths of the sky
Observers found eighths easier to judge than tenths: halve the sky, halve again, halve again. The okta became the international standard in 1949.
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BKN is not broken weather
Broken (BKN) means 5–7 oktas, mostly cloudy, and is the lowest layer that counts as a ceiling for pilots.
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Background
About oktas
Weather observers split the sky into eighths, oktas: 0 is clear, 4 is half covered, 8 is overcast. Aviation reports (METAR) group them: FEW (1–2 oktas), SCT scattered (3–4), BKN broken (5–7) and OVC overcast (8).