Open any aviation weather map and you'll see airports colored green, blue, red or magenta. Those colors are flight categories. They sum up the ceiling and visibility at a glance, so a pilot can tell in seconds whether the weather is good, marginal or instrument-only.
The Four Categories
| Category | Ceiling | Visibility |
|---|---|---|
| VFR | Above 3,000 feet | And more than 5 miles |
| MVFR | 1,000 to 3,000 feet | And/or 3 to 5 miles |
| IFR | 500 to below 1,000 feet | And/or 1 to less than 3 miles |
| LIFR | Below 500 feet | And/or less than 1 mile |
The worse of the two values decides the category. A 4,000-foot ceiling with 4 miles of visibility is MVFR, not VFR.
Flight Categories Aren't Legal Minimums
The categories are a quick summary from the National Weather Service. The legal VFR weather minimums are in 14 CFR 91.155 and depend on the airspace. In Class D airspace like Van Nuys, for example, you need 3 miles of visibility and a 1,000-foot ceiling. An airport can be MVFR and still be legal for VFR flight, which is exactly why students need their own personal minimums.
What Each Category Means For A Student Pilot
- VFR: Normal training. Pattern work, maneuvers and cross-countries.
- MVFR: Legal, but your instructor decides. Solo flights usually wait.
- IFR: VFR flight is off. Instrument students can train in the clouds with an instructor.
- LIFR: Everyone stays on the ground, or in the simulator.
The Marine Layer In Los Angeles
Southern California's most common "bad weather" is a low marine layer that rolls in overnight, especially in late spring and early summer. It often shows up as IFR or MVFR along the coast in the morning, then burns off by late morning or midday. Van Nuys sits inland in the San Fernando Valley, so it often clears earlier than coastal airports. When it doesn't, we move lessons later in the day or into our full-motion simulator. See our weather and cancellation policy.
Frequently Asked Questions
What Does MVFR Stand For?
Marginal visual flight rules: ceiling 1,000 to 3,000 feet and/or visibility 3 to 5 miles.
Can I Fly VFR When An Airport Is MVFR?
Often, yes, if the weather meets the 91.155 minimums for that airspace. Whether you should is a question for your personal minimums and your instructor.
Where Can I Check Van Nuys Weather?
Our Van Nuys Airport Weather Today page shows current conditions and what they mean for your lesson.
More Guides For Student Pilots
- Aviation weather hazards — turbulence, wind shear, icing, the marine layer and Santa Ana winds.
- How to read a METAR and TAF — a real Van Nuys report decoded line by line.
- What is VFR — visual flight rules, weather minimums and cruising altitudes.
