Definition
In the context of sky cover and ceilings, 'partial' describes a sky condition in which an obscuring phenomenon (such as fog, smoke, or dust) hides part of the sky from the ground observer's view, but not all of it. A partial obscuration means that less than the full sky is hidden, with the obscured portion reported in eighths of total sky coverage.
Plain English
Some — but not all — of the sky is blocked from view by something like fog or smoke. You can still see part of the sky through it.
Context Anchor
Seen in weather and ceiling discussions, especially when deciding what reported sky condition counts as the ceiling.
Derivation
From Latin 'partialis', meaning 'of a part'. In aviation weather, it keeps that plain meaning: only a part of the sky is affected, not the whole.
Why Pilots Care
Knowing a ceiling is partial helps pilots judge whether enough visual references remain for continued VFR flight or if instrument procedures are needed.
Grounding Statement
If fog, cloud, or another condition blocks only part of the observed sky, it may be described as partial rather than treated as a full ceiling.
Intuition Check
Do not read partial as “unimportant.” Here it means “only part of the sky or view is affected,” even though that part may still matter to the pilot.
Example Sentence 1
The METAR indicated a partial obscuration due to fog, with three-eighths of the sky hidden from the observer.
Example Sentence 2
With partial coverage the pilot could still see the runway environment on final approach.