What does "OVC" indicate in a METAR report?

In METAR reports, "OVC" denotes that the sky is overcast, meaning that clouds cover all of the sky or 8/8ths of the celestial dome. This is significant for aviation and weather reporting because it indicates limited visibility due to cloud cover, potentially affecting flight operations and weather observation. By understanding that "OVC" represents complete cloud coverage, one can assess the weather conditions more accurately, noting the potential for reduced visibility and the necessity for instrument flying in aviation.

The other terms, while related to cloud cover, denotate different levels of sky visibility and cloud aggregation. Scattered clouds would imply a less dense cloud coverage than overcast, and partially cloudy skies indicate varying degrees of visibility, but not full coverage. Clear skies with limited visibility is contrary to the concept of "OVC," as overcast conditions imply the opposite of clear skies, which would show less obscuring cloud presence.