Plain English Meaning

Bad weather where the clouds are very low and you can't see far, so a pilot must rely almost entirely on instruments to fly safely.

Full Definition

Weather conditions in which cloud bases, visibility, or both are near the minimum values that allow flight under Instrument Meteorological Conditions (IMC) — typically low ceilings, reduced visibility, and limited room for error during instrument approaches and departures.

Context Anchor

Seen in instrument training when discussing actual weather conditions used to teach instrument flying, especially departures and in clouds or poor visibility.