VFR, MVFR, IFR, LIFR explained
Almost every flight-weather app and METAR decoder shows one of these four categories: VFR, MVFR, IFR or LIFR. They roll ceiling and visibility into a quick assessment – but, upfront, they are not the official definition of VFR minimum conditions. This article explains what the letters mean and where the line to real VFR minima runs.
The four categories
- VFR – ceiling above 3,000 ft AGL and visibility above 5 SM (~8 km).
- MVFR (Marginal VFR) – ceiling 1,000–3,000 ft AGL or visibility 3–5 SM.
- IFR – ceiling 500–1,000 ft AGL or visibility 1–3 SM.
- LIFR (Low IFR) – ceiling below 500 ft AGL or visibility below 1 SM.
If ceiling and visibility fall into different tiers, whichever is worse governs. A ceiling is the lowest cloud layer reported as BKN or OVC – few (FEW) or scattered (SCT) cloud doesn't count. All codes are in the METAR/TAF glossary.
Two examples
BKN018, visibility 4 SM: a 1,800 ft ceiling falls into the MVFR range (1,000–3,000 ft), 4 SM visibility is also MVFR (3–5 SM) → overall category MVFR.
OVC004, visibility 6 SM: a 400 ft ceiling falls into the LIFR range (below 500 ft), even though visibility alone would be VFR → the worse value wins, overall category LIFR.
Why this isn't the official VFR minima
This four-tier classification originated in the US and is used worldwide as a practical rule-of-thumb for weather conditions – including in places where it has no legal standing. Whether VFR flight is actually permitted in a given airspace is governed in Europe by the official VFR minima under SERA, which prescribe different minimum visibility and cloud-clearance values depending on airspace class and altitude – more on that in VFR minima by airspace class. A METAR category of "VFR" means: generally good weather – not automatically: legally permitted in every airspace.
Frequently asked questions
Are VFR/MVFR/IFR/LIFR official legal terms?
No. This is a common, originally US-based classification for quick weather assessment, used worldwide as a practical rule-of-thumb even outside the US – not the official VFR minima by airspace class.
What counts as a ceiling?
The lowest cloud layer reported as BKN (5–7 oktas) or OVC (8 oktas), or a reported vertical visibility. Few (FEW) or scattered (SCT) cloud doesn't count as a ceiling.
What if ceiling and visibility fall into different categories?
Whichever value is worse determines the overall category.
What's next?
The four categories are a good first reference point, but they replace neither the official VFR minima nor a full METAR reading. The central flight weather assessment in VFR Wetter shows the AWC category alongside its own multi-level assessment (Flyable/Marginal/No-go).
This article does not replace aviation training or an official flight weather briefing. Whether VFR flight is legally permitted depends exclusively on the applicable regulations, not on this categorization.