"Sky days" refers to the number of days that something is visible or present in the sky. It could refer to the number of days with clear or cloudy skies, or the duration of an event or phenomenon happening in the sky.
Sentences with «sky days»
We had 2 blue sky days in a row (which means they're busy somewhere else). (geoengineeringwatch.org)
Most of the region will see partly cloudy skies each day. (costaricantimes.com)
Ever wanted to see first - hand what it's like to be a pilot, roaming the friendly skies day - in and day - out? (travelandleisure.com)