Definition
A sky condition in which clouds cover more than 8/8 (effectively all) of the celestial dome, reported in aviation weather as OVC. Overcast indicates a continuous cloud layer with no significant breaks, and when the layer is below 1,000 feet AGL or below the published minimum, it constitutes a ceiling.
Plain English
The sky is completely covered by a single layer of cloud, with no meaningful gaps to see through.
Context Anchor
Pilots encounter overcast in weather reports, preflight planning, and in flight when judging visibility, cloud height, and available outside visual references.
Derivation
From Middle English 'overcasten' meaning 'to cover over' or 'cast across.' The original sense of something being thrown over the top fits the image of cloud spread completely across the sky.
Why Pilots Care
Overcast conditions set the ceiling and often force a choice between continuing under visual flight rules or switching to instruments.
Grounding Statement
Picture looking up and seeing one continuous cloud cover from horizon to horizon instead of separate clouds with blue sky between them.
Intuition Check
Overcast does not just mean “cloudy.” In aviation, it means the entire sky is covered by clouds from the observer’s viewpoint.
Example Sentence 1
The METAR reported OVC008, so the pilot planned an instrument approach into the destination.
Example Sentence 2
With the sky overcast, the student pilot could no longer use ground landmarks for navigation and had to rely on instruments.