For the total cloud amount, codes 0 to 8 show the fraction, in octas, 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, no clouds in the sky |
| 1 | 1 octa or less, but not zero |
| 2-6 | 2-6 octas |
| 7 | 7 octas or more, but not 8 octas |
| 8 | 8 octas, no blue in the sky |
Scientific contact: Professor Sandra Yuter