VFR Weather Minimums by Airspace Class

The rule that decides how much weather you may legally fly a VFR airplane into is one section long. 14 CFR 91.155 asks two questions continuously for the whole flight: how far can you see, and how far are you from the nearest cloud. The required answers change with the class of airspace you are in, with your altitude, and, in Class G, with whether the sun is up.

Most of us carry a compressed version in our heads. Three miles, five hundred below, a thousand above, two thousand horizontal. That version is right in Class C, Class D, and Class E below 10,000 ft MSL, which covers the majority of GA flying. It is wrong in Class B, where the cloud numbers collapse to clear of clouds. It is wrong at or above 10,000 ft MSL, where visibility goes to 5 miles and the cloud box grows. And it is wrong in Class G in four separate ways, which is where most of the reproduced charts floating around the internet fall apart.

What follows is the table as the regulation writes it, transcribed from the current eCFR text of 91.155. The section was last amended in 2014 by Amdt. 91-330A, and the text in force in August 2026 carries no changes since.

The 91.155 table, as the regulation writes it

Airspace	When	Flight visibility	Distance from clouds
Class A	Any time	Not applicable	Not applicable
Class B	Any time	3 SM	Clear of clouds
Class C	Any time	3 SM	500 below, 1,000 above, 2,000 horizontal
Class D	Any time	3 SM	500 below, 1,000 above, 2,000 horizontal
Class E, less than 10,000 ft MSL	Any time	3 SM	500 below, 1,000 above, 2,000 horizontal
Class E, at or above 10,000 ft MSL	Any time	5 SM	1,000 below, 1,000 above, 1 SM horizontal
Class G, 1,200 ft or less AGL (regardless of MSL altitude)	Day	1 SM	Clear of clouds
Class G, 1,200 ft or less AGL (regardless of MSL altitude)	Night	3 SM	500 below, 1,000 above, 2,000 horizontal
Class G, 1,200 ft or less AGL, helicopter	Day	1/2 SM	Clear of clouds
Class G, 1,200 ft or less AGL, helicopter	Night	1 SM	Clear of clouds
Class G, more than 1,200 ft AGL but less than 10,000 ft MSL	Day	1 SM	500 below, 1,000 above, 2,000 horizontal
Class G, more than 1,200 ft AGL but less than 10,000 ft MSL	Night	3 SM	500 below, 1,000 above, 2,000 horizontal
Class G, more than 1,200 ft AGL and at or above 10,000 ft MSL	Day or night	5 SM	1,000 below, 1,000 above, 1 SM horizontal

Three things belong with that table rather than after it.

The four Class G rows that mention day or night at 1,200 ft AGL and below each carry the qualifier “except as provided in § 91.155(b)” in the original. Paragraph (b) is a narrow airport-traffic-pattern relief, and it gets its own treatment below.

Class A reads “not applicable” because VFR is not available in Class A at all, not because the weather stops mattering up there.

And the final Class G row has no day or night column, because the regulation does not give it one. At or above 10,000 ft MSL in Class G, the requirement is 5 miles and 1,000/1,000/1 statute mile around the clock. Any chart that runs a night column down the whole Class G block and prints 3 miles in that last cell has invented a rule.

The same table is reprinted in AIM paragraph 3-1-4, Basic VFR Weather Minimums, which is a useful cross-check when someone hands you a chart and you want a second primary source in thirty seconds.

Why the numbers change with the airspace

The whole table exists to serve one job. AIM 3-3-2 states it plainly: the rules governing VFR flight were adopted to help the pilot meet the responsibility to see and avoid other aircraft. That responsibility itself lives in 14 CFR 91.113(b), which requires vigilance to see and avoid regardless of whether the flight is VFR or IFR.

Read as a time budget, the numbers stop looking arbitrary. Three statute miles is about 2.6 nautical miles. Two airplanes converging head-on at 120 knots each close that in a little under 40 seconds, which is roughly the time a human needs to acquire a small target, decide, and move the airplane. One statute mile at 100 knots each is under 16 seconds, which is why the 1-mile allowance exists only down low in uncontrolled airspace where traffic is thin and slow.

The cloud-clearance numbers do a different job. They keep VFR traffic far enough from the edge of a cloud that an IFR aircraft popping out of it still has room. The 500-below, 1,000-above asymmetry reflects where IFR traffic actually is: cruising IFR altitudes sit on top of layers more often than underneath them, so the reg buys more vertical room above.

Two special cases explain themselves once you know what the airspace is doing.

Class B trades cloud clearance for clear of clouds. Every aircraft inside Class B is there on an ATC clearance under 91.131(a)(1), and the controller is separating everyone. Separation is not your problem in Class B. Not flying into a cloud is. So the reg keeps the 3-mile visibility and drops the geometry.

The 10,000 ft MSL step is a speed limit expiring. Below 10,000 ft MSL, 91.117(a) caps indicated airspeed at 250 knots. Above it, that cap goes away, closure rates climb, and the reg buys the seconds back with 5 miles and a bigger cloud box.

One more mechanic worth knowing before the Class G section: when airspace designations overlap, AIM 3-1-3 says the operating rules of the more restrictive designation apply. You never get to pick the friendlier row.

Class G is where the reproduced charts go wrong

Class G carries four altitude tiers, a day/night split in two of them, and separate helicopter rows. It is the busiest block in the table and the one most often copied badly. Four details do most of the damage.

“Regardless of MSL altitude” is load-bearing. The 1,200-ft-or-less tier applies at any MSL altitude. Fly outside a charted transition area over 12,000 ft terrain in the Rockies, at 12,800 ft MSL and 800 ft above the ridge, and you are in Class G within 1,200 ft of the surface. Daytime minimums there are 1 statute mile and clear of clouds, not the 5 miles the 10,000 ft MSL rows would suggest. The parenthetical exists precisely to settle that argument.

“One mile and clear of clouds” is not all of daytime Class G. Cross 1,200 ft AGL by day and the visibility stays at 1 mile, but clear of clouds becomes 500 below, 1,000 above, 2,000 horizontal. Same visibility, completely different cloud geometry. This is the single most-dropped distinction in the reproduced charts, and it is the one that bites on a scud run, because the airplane climbing to stay legal on visibility can go illegal on cloud clearance in the same 60 seconds.

Night takes away clear of clouds down low. At 1,200 ft AGL and below at night, the requirement is 3 miles and the standard 500/1,000/2,000. The generous daytime allowance is a daytime allowance.

Above 10,000 ft MSL there is no night row. Five miles and 1,000/1,000/1 statute mile, day or night, in Class G exactly as in Class E.

The 91.155(b) traffic-pattern exceptions

Paragraph (b) carves out two operations in Class G below 1,200 ft AGL, and both are pattern-only.

A helicopter may operate clear of clouds in an airport traffic pattern within half a mile of the runway or helipad of intended landing if flight visibility is at least half a statute mile.

An airplane, powered parachute, or weight-shift-control aircraft may operate clear of clouds at night, in an airport traffic pattern within half a mile of the runway, when visibility is less than 3 statute miles but not less than 1. The wording matters: “in an airport traffic pattern within one-half mile of the runway.” It is relief for the circuit, not for the departure, and the moment you leave the pattern the 3-mile night number is back.

Where Class G above 1,200 ft AGL actually exists

Those upper Class G rows are not hypothetical, but they are regional. Per AIM 3-2-6, Class E transition areas start at either 700 ft AGL, shown as the magenta vignette on a sectional, or 1,200 ft AGL, shown as the blue vignette. Outside both, Class E generally does not begin until 14,500 ft MSL, so Class G runs from the surface all the way up. That is the terrain where the “more than 1,200 ft AGL” rows govern real flying, and it is mostly the mountain west and remote areas.

There is a tidy edge case in paragraph (e). An aircraft operating at the base altitude of a Class E area is considered to be in the airspace directly below it. Level at exactly 700 ft AGL under a 700-foot Class E floor, you are legally in Class G, on the Class G row. The rule breaks the tie in your favor, and it is a favorite oral-exam question.

The two airport rules pilots forget

Paragraphs (c) and (d) sit below the table, and neither one shows up on the chart most pilots memorize. Both can stop a flight that clears every number in paragraph (a).

Paragraph (c), the 1,000 ft ceiling. No person may operate an aircraft beneath the ceiling under VFR within the lateral boundaries of controlled airspace designated to the surface for an airport when the ceiling is less than 1,000 feet. That covers Class B, C, and D surface areas and Class E surface areas. It says nothing about your visibility. An 800 ft overcast closes VFR flight beneath it inside that surface area even with 10 miles underneath.

Note the word “beneath.” Paragraph (c) does not reach an aircraft on top of the layer, so a VFR overflight above the ceiling is untouched by (c), though still bound by (a).

“Ceiling” here is the term defined in 14 CFR 1.1: the height of the lowest layer reported as broken, overcast, or obscuration and not classified as thin or partial. Scattered never makes a ceiling, no matter how solid it looks off the nose. How that plays out on a weather display, and why a field can read IFR on a website while the FARs say something else, is the subject of our guide to what VFR, MVFR, IFR and LIFR actually mean.

Paragraph (d), 3 miles to take off, land, or enter the pattern. Inside the lateral boundaries of the surface areas of Class B, C, D, or E airspace designated for an airport, you may not take off, land, or enter the traffic pattern under VFR unless ground visibility at that airport is at least 3 statute miles. If ground visibility is not reported there, flight visibility during landing, takeoff, or in the pattern must be at least 3 miles.

Two consequences. First, where visibility is reported, the reported number governs the takeoff, not your assessment out the window. Second, (d) reaches takeoff, landing, and pattern entry only. A transit through the surface area above pattern altitude is governed by (a) and (c) instead.

One field, run through all three paragraphs

Take the kind of observation that looks survivable and is not. Centennial (KAPA) sits under a Class D surface area. Plain English first: at 1553Z, wind from 140 at 8 knots, visibility 4 statute miles in mist, a broken layer at 900 ft, temperature 12 °C, dew point 11 °C, altimeter 30.02.

KAPA 151553Z 14008KT 4SM BR BKN009 12/11 A3002

If the contractions in that line are not automatic yet, our METAR decoder will read it back in full, and the glossary covers the individual codes.

Now the three tests, in order. Paragraph (d) passes: ground visibility is 4 miles, above the 3-mile floor for departing a Class D surface area. Paragraph (a) fails: a broken layer at 900 ft is a cloud you must stay 500 ft below, which puts your legal ceiling at 400 ft AGL, and no pattern fits under that. Paragraph (c) fails independently and more bluntly: the ceiling is 900 ft, below 1,000, inside controlled airspace designated to the surface for an airport, so VFR beneath it is prohibited outright.

Two independent stoppers, from one benign-looking observation, and only one of them appears on the memorized chart. The remaining legal option is a Special VFR clearance, which substitutes its own numbers and comes with conditions of its own. We cover when it is available and when it is a bad idea in our guide to Special VFR.

Night changes Class G and nothing else

The night effect in 91.155 is narrower than most pilots assume, and it is entirely inside Class G.

Below 1,200 ft AGL, 1 mile and clear of clouds becomes 3 miles and 500/1,000/2,000. Between 1,200 ft AGL and 10,000 ft MSL, 1 mile becomes 3 miles with the cloud clearances unchanged. That is the whole of it. Class B, Class C, Class D, and Class E carry identical numbers at 0200Z and at 1400Z.

Which “night” triggers it matters, because aviation uses the word three different ways. The one 91.155 runs on is the definition in 14 CFR 1.1: the time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the Air Almanac and converted to local time. Not sunset. Civil twilight typically ends 20 to 30 minutes after sunset at mid-latitudes, so there is a real window each evening where your position lights are already required under 91.209(a), which runs from sunset, while the Class G night minimums have not yet taken effect. Our civil twilight calculator gives you all three boundaries for tonight at your field.

The legal picture is also the least interesting part of night weather. A 3-mile night visibility over unlit terrain buys you far less than 3 miles over a suburb, and the horizon you were using to stay upright may not exist. Night flying weather margins makes the case for a separate and higher set of numbers after dark.

Flight visibility is your judgment, ground visibility is a report

91.155(a) is written entirely in terms of flight visibility, and paragraph (d) is the one place the regulation reaches for ground visibility. The two are defined separately in 14 CFR 1.1 and they are not interchangeable.

Flight visibility is the average forward horizontal distance, from the cockpit in flight, at which prominent unlighted objects are visible by day and prominent lighted objects by night. Nobody measures it for you. It is a determination the pilot in command makes, in the airplane, in real time, and it is the number every row of the table is testing.

Ground visibility is prevailing horizontal visibility near the surface, as reported by the National Weather Service or an accredited observer. It is what the visibility group in a METAR is telling you, and it describes one point on the field at one moment.

The gap between them is where trouble lives. A METAR reporting 6 miles at the sensor says nothing about the flight visibility at 2,500 ft over a ridge 12 miles away, and slant-range visibility through haze toward a runway is routinely worse than the horizontal figure suggests. The observation is an input to the decision, not the decision. Our comparison of what a METAR and a TAF each tell you covers what those products can and cannot promise about the air you are about to fly through.

The table is a floor, not a plan

Everything above is the legal boundary. It describes the worst conditions in which a flight is not a violation. It says nothing about whether the flight is a good idea, and the two questions have different answers more often than the numbers suggest.

Paragraph (a) was written for a current, proficient pilot who is comfortable in the airplane and not tired or rushed. Flown at the bottom of the range, 3 miles and 500 below a ragged base in a haze layer is a demanding VFR day, and 1 mile and clear of clouds in Class G is a scud run with legal cover. Nearly every continued-VFR-into-IMC accident began with a pilot who was legal at the departure end, which is the subject of how VFR into IMC actually happens. The numbers you should be flying are the ones you set in advance, above the table, at your desk. That is the whole argument in our go/no-go framework.

A few things sit outside 91.155 entirely and are worth knowing by name.

Special VFR is the relief valve for surface areas, with its own numbers in 14 CFR 91.157, available only inside the surface area of controlled airspace designated for an airport, below 10,000 ft MSL, and only on pilot request with an ATC clearance.

Student pilots carry a stricter floor than 91.155 gives them. 14 CFR 61.89(a)(6) prohibits acting as pilot in command with flight or surface visibility below 3 statute miles by day or 5 at night, and (a)(7) requires that the flight can be made with visual reference to the surface. Those limits stack on top of the table; the Class G 1-mile row is simply unavailable to a student.

IFR planning has an unrelated set of weather numbers, driven by the forecast at your ETA rather than by conditions now. The 1-2-3 rule and what an alternate has to meet are covered in IFR alternate requirements.

If you are about to explain any of this to an examiner, the table is a near-certain oral item and paragraphs (c) and (d) are where the follow-up questions go. Our rundown of the weather questions that come up on the private pilot checkride covers how to answer them without reciting.

The reg is short enough to read in five minutes, and it is worth reading in the original rather than in someone’s redrawn chart. Bookmark the eCFR page for 91.155. It is the version that is current, and it is the version that counts.

Common questions

Can I legally fly VFR above a solid cloud layer?

Under Part 91, yes, provided you meet the 91.155 visibility and cloud-clearance numbers for the airspace you are in and can get up and down legally. No Part 91 rule requires a non-student pilot to keep the surface in sight. Student pilots are the exception: 14 CFR 61.89(a)(7) prohibits a solo flight that cannot be made with visual reference to the surface.

What are the VFR weather minimums for helicopters?

Helicopters get their own Class G rows at 1,200 ft AGL and below: half a statute mile and clear of clouds by day, 1 statute mile and clear of clouds at night. Above 1,200 ft AGL, and in every other class of airspace, a helicopter flies the same numbers as an airplane. Paragraph 91.155(b)(1) adds a half-mile flight visibility, clear-of-clouds allowance in an airport traffic pattern.

Do student pilots have different VFR weather minimums?

Yes, and they are stricter than 91.155. Under 14 CFR 61.89(a)(6) a student pilot may not act as pilot in command with flight or surface visibility below 3 statute miles by day or 5 statute miles at night. Paragraph (a)(7) adds that the flight must be able to be made with visual reference to the surface. Those limits stack on top of 91.155, never below it.

How is Special VFR different from the 91.155 minimums?

Special VFR is a separate set of numbers in 14 CFR 91.157 that applies only inside the surface area of controlled airspace designated for an airport, below 10,000 ft MSL, and only when you request it and ATC clears you for it. It substitutes 1 statute mile and clear of clouds for the 91.155 table, which is how a field with an 800 ft ceiling can still be legally departed.