What, precisely, does partly cloudy mean? Forecasters use these descriptions of sky condition based upon tenths of the sky covered by opaque (not transparent) clouds.
| Sky Condition | Cloud Coverage |
|---|---|
| Cloudy | 8/8 Opaque Clouds |
| Mostly Cloudy, or Considerable Cloudiness | 6/8 to 7/8 |
| Partly Cloudy, or Partly Sunny | 3/8 to 5/8 |
| Mostly Clear, or Mostly Sunny | 1/8 to 2/8 |
| Clear, or Sunny | 0/8 Opaque Clouds |