Definition
Weather conditions below the minimum prescribed by regulation, instrument approach procedure, or operations specifications for a particular operation. For a pilot, this means conditions are below the limits authorized for the pilot's certification or currency. For an instrument approach, it means visibility or ceiling is below the minimums published for that approach.
Plain English
The weather is worse than what the rules allow you to fly in, or worse than what the approach you want to use permits.
Context Anchor
You will see this in weather, approach, takeoff, landing, and airport status discussions when deciding whether an operation is allowed to continue.
Derivation
Minimum comes from a Latin word meaning “smallest.” In aviation, “minimums” are the lowest allowed values for a specific operation. “Below minimums” means the actual conditions have dropped under that allowed limit.
Why Pilots Care
Continuing an operation below minimums violates regulations and sharply raises the chance of controlled flight into terrain or loss of situational awareness.
Intuition Check
Do not read “below minimums” as simply “not ideal.” In aviation, it means the conditions are under a required limit for that specific operation.
Example Sentence 1
The tower reported visibility at one-quarter mile, which was below minimums for the ILS approach, so we diverted to our alternate.
Example Sentence 2
Even with the runway in sight, the ceiling remained below minimums so the crew executed the missed approach.