Definition
The minimum flight visibility required by regulation for a pilot to legally operate an aircraft under Visual Flight Rules. The exact value depends on altitude, airspace class, and time of day, and is set out in 14 CFR Part 91.155.
Plain English
The shortest distance you must be able to see ahead in order to legally fly using your eyes alone, without relying on instruments. If you can't see at least that far, you're not allowed to fly under VFR.
Context Anchor
Seen in weather minimums, airspace rules, and preflight planning when deciding whether a flight may be conducted under Visual Flight Rules.
Derivation
VFR stands for Visual Flight Rules — the set of rules for flying by outside visual reference. 'Visibility minimum' simply means the lowest visibility allowed. The phrase exists because the rules set a floor below which visual flying is no longer considered safe or legal.
Why Pilots Care
Meeting the minimum ensures the pilot can see and avoid other aircraft, terrain, and obstacles without relying on instruments.
Grounding Statement
Before flying visually, the pilot must be able to see far enough to meet the rule for that airspace and situation.
Intuition Check
Do not read “visibility minimum” as just “how clear it looks to me.” In this context, it means a specific legal visibility requirement tied to the airspace and conditions.
Example Sentence 1
The forecast showed visibility dropping to two miles, which is below the VFR visibility minimum for that airspace, so the pilot delayed the departure.
Example Sentence 2
In Class E airspace below 10,000 feet, the VFR visibility minimum is 3 statute miles.