Definition
A category of flight conditions used on weather depiction and graphical aviation weather products in which the ceiling is between 1,000 and 3,000 feet above ground level, and/or visibility is between 3 and 5 statute miles inclusive. MVFR conditions are legal for VFR flight in most airspace but are close enough to instrument conditions that they require additional caution. On weather charts, MVFR areas are shown shaded in blue.
Plain English
Weather that is still good enough for flying by visual reference, but only just. The clouds are lower or visibility is poorer than ideal, so a non-instrument-rated pilot should think carefully before going.
Context Anchor
Seen on aviation weather products such as weather depiction charts, where areas are grouped by how much cloud height and visibility pilots can expect.
Derivation
‘Marginal’ comes from the Latin margo, meaning ‘edge or border.’ MVFR conditions sit right at the edge of legal visual flight — close to the boundary where VFR ends and IFR begins.
Why Pilots Care
Pilots use it to decide whether visual flight remains practical or whether filing IFR becomes the safer choice.
Intuition Check
Marginal does not automatically mean unsafe or illegal. In this FAA weather category, it means the ceiling and/or visibility fall within specific low-but-not-lowest ranges.
Example Sentence 1
The weather depiction chart showed a wide band of MVFR across the route, so the pilot rechecked ceilings and visibilities before departing.
Example Sentence 2
Even though the airport reported MVFR, the pilot maintained visual contact with the ground throughout the short flight.