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VFR, MVFR, IFR, LIFR – Flight Categories Explained

Aviation Weather Guide · 4 min read

Flight categories are a quick way to summarize weather conditions at an airport based on two key factors: ceiling and visibility. They're color-coded on weather maps and tools like WxBriefPro to give pilots instant situational awareness.

The Four Categories

CategoryCeilingVisibility
VFR – Visual Flight Rules > 3,000 ft AGL > 5 statute miles
MVFR – Marginal VFR 1,000–3,000 ft AGL 3–5 statute miles
IFR – Instrument Flight Rules 500–999 ft AGL 1–3 statute miles
LIFR – Low IFR < 500 ft AGL < 1 statute mile

The category is determined by whichever factor (ceiling or visibility) puts it in the lower category.

What Is a Ceiling?

The ceiling is the height of the lowest broken (BKN) or overcast (OVC) layer in a METAR or TAF. FEW and SCT layers do not count as the ceiling. Vertical visibility (VV) also counts as a ceiling when the sky is obscured.

What Does Each Category Mean for Pilots?

VFR

Good flying weather. VFR pilots can legally fly under FAR Part 91 VFR minimums. Always verify you meet the specific airspace requirements (Class B/C/D/E/G each have their own minimums).

MVFR

Technically still VFR, but conditions are marginal. Student pilots and low-time pilots should be cautious — conditions can deteriorate quickly. A solid alternate plan is wise.

IFR

VFR flight is not legal or safe without an instrument rating and an IFR-equipped aircraft. Even instrument-rated pilots should review approach minimums carefully — many approaches require better than basic IFR conditions.

LIFR

Extremely low conditions. Many instrument approaches are not usable. Even experienced IFR pilots may find the destination below minimums. Divert planning is critical.

The "Worse of the Two" Rule

If ceiling is VFR but visibility is IFR, the station is classified as IFR. The category always reflects the worse of the two factors. WxBriefPro applies this logic automatically when color-coding your briefing.

Personal Minimums

Legal minimums are a floor, not a target. Most experienced pilots set personal minimums well above the legal floor — for example, no VFR flight below 2,000 ft ceiling / 5 SM visibility until they have 200+ hours. Build your own personal minimums and stick to them.

Check Flight Categories on WxBriefPro