Definition
Weather conditions below the minimum visibility and cloud clearance values prescribed for visual flight. When IFR conditions exist, flight is permitted only under Instrument Flight Rules, which require an instrument rating, an IFR flight plan, and an ATC clearance.
Plain English
Weather that is too poor to fly by looking outside. The clouds are too low or visibility is too limited, so the flight has to be conducted using instruments and under air traffic control.
Context Anchor
Seen in weather reports, flight planning, pilot briefings, and discussions about whether a flight can be made under visual rules or must be conducted under instrument rules.
Derivation
IFR stands for Instrument Flight Rules. 'Conditions' here refers specifically to the weather state, not aircraft condition or pilot condition. So 'IFR Conditions' means 'weather requiring instrument flight rules.'
Why Pilots Care
Determines whether an instrument rating, IFR-equipped aircraft, and an IFR flight plan are required for legal and safe operation.
Grounding Statement
If the clouds are too low or the visibility is too poor for visual-rule flying, the weather is in IFR conditions.
Intuition Check
IFR conditions describe the weather, not the flight plan. A pilot can be on an IFR flight plan in good weather, and weather can become IFR even before a pilot has received an IFR clearance.
Example Sentence 1
The destination airport reported a 400-foot ceiling and one-mile visibility, which are IFR conditions, so the VFR-only pilot diverted to a nearby field with better weather.
Example Sentence 2
With IFR conditions forecast along the route, the crew reviewed the instrument approach procedures before departure.