Overcast

Meteorological condition
title: "Overcast" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["clouds"] description: "Meteorological condition" topic_path: "general/clouds" source: "https://en.wikipedia.org/wiki/Overcast" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Meteorological condition ::
::figure[src="https://upload.wikimedia.org/wikipedia/commons/2/2f/Overcast_Mehamn.jpg" caption="A completely overcast sky in [[Mehamn]], Norway."] ::
Overcast or overcast weather, as defined by the World Meteorological Organization, is the meteorological condition of clouds obscuring at least 95% of the sky. However, the total cloud cover must not be entirely due to obscuring phenomena near the surface, such as fog.
Definition
Overcast, written as "OVC" in the METAR observation, is reported when the cloud cover is observed to equal eight oktas (eighths). An overcast sky may be explicitly identified as thin (mostly transparent), but otherwise considered opaque—which always constitutes a ceiling in aviation meteorology.
Appearance
Sometimes clouds can be of different colors such as black or white, but overcast usually refers to darker skies. In some cases, it can be characterized by almost zero distinction of borders of clouds. Or the sky may be covered by a single type of cloud, such as stratus, turning the whole sky into a dull white color.
Length
Periods of overcast weather can range from a few hours to several days. Overcast weather can also affect people suffering from seasonal affective disorder.
The same weather when observed from above may be referred to as undercast, generally by pilots reporting in-flight weather conditions.
References
References
- "Aerodrome Weather Report". [[World Meteorological Organization]].
- "Overcast". [[American Meteorological Society]].
- World Meteorological Organization. "Overcast". Eumetcal.
- ''Oxford English Dictionary'', 3rd ed. (website), s.v. “overcast," 2a and 2b. http://www.oed.com/view/Entry/134377#eid32922408 (Accessed September 7, 2016).
- "Undercast". [[American Meteorological Society]].
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