For the total cloud amount, codes 0 to 8 show the fraction, in oktas, of the celestial dome covered by all clouds. An octa is one eighth of the celestial dome, so we estimate how many eighths of the celestial dome are covered up by clouds.
| Code | Definition |
|---|---|
| 0 | Clear |
| 1 | 1 okta or less, but not zero |
| 2-6 | 2-6 oktas |
| 7 | 7 oktas or more, but not 8 oktas |
| 8 | 8 oktas |
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