VFR Weather Minimums by Airspace, Made Memorable

The VFR weather minimum most pilots can recite, 3 statute miles with 500 feet below, 1,000 above and 2,000 horizontal from clouds, is one row of a table in 14 CFR 91.155 that has eleven rows for airplanes. The row that applies to you changes with the class of airspace, with your height relative to 1,200 feet AGL and 10,000 feet MSL, and with day or night. Two rows point to an exception in another paragraph, and the whole table yields to special VFR.

That is why "3-152" gets students through the written and then gets them into trouble on a hazy afternoon under a Class E shelf. The minimum at 1,100 feet over farmland is not the minimum 500 feet higher.

The full 91.155 table

The figures are the airplane rows of the table in 14 CFR 91.155(a), which the AIM reprints in AIM 3-1-4 (AIM Basic with Change 3, effective July 9, 2026). Helicopters have their own, lower Class G rows and are left out here.

The visibility column only ever says 1, 3 or 5. The cloud clearance column only ever says clear of clouds, 500/1,000/2,000, or 1,000/1,000/1 SM. The airspace column does the work: five classes, two altitude qualifiers, day or night.

What the 1,200 AGL and 10,000 MSL qualifiers do

The two altitude lines in 91.155(a) are measured differently. The 1,200 foot line is AGL and appears only in the Class G rows; the 10,000 foot line is MSL and appears in both the Class E and the Class G rows.

At or below 1,200 feet AGL in Class G, the rule says "regardless of MSL altitude", so a pilot flying 1,000 feet above a 9,500 foot plateau by day needs 1 statute mile and clear of clouds, even though the altimeter reads over 10,000. Climb to 1,300 feet above that plateau and the row changes to more than 1,200 feet AGL and at or above 10,000 feet MSL: 5 statute miles, 1,000 feet above and below, 1 mile horizontal. The common mistake is to remember "5 miles above 10,000" and forget that in Class G it only applies once you are also more than 1,200 feet up.

Class E has no AGL qualifier at all. Below 10,000 feet MSL it is 3 SM and 500/1,000/2,000; at or above 10,000 feet MSL it is 5 SM and 1,000/1,000/1 SM. Where Class E begins at 700 feet AGL over a high-elevation airport, you can be in the 5 mile row while still in the traffic pattern.

91.155(e) adds that an aircraft operating at the base altitude of a Class E area is considered to be in the airspace below it. At 1,200 feet AGL under a 1,200 foot floor you are in Class G. One foot higher, Class E. Nobody holds altitude to the foot, which is the argument for treating a floor as a 200 foot band rather than a line. Class E airspace: 700 ft vs 1,200 ft covers where those floors come from.

Class G at night has one exception for the traffic pattern

By night in Class G at or below 1,200 feet AGL, the table demands 3 statute miles and the full 500/1,000/2,000 cloud clearance, the same as Class E. Paragraph 91.155(b)(2) carves out one case: if the visibility is less than 3 statute miles but not less than 1 statute mile, and you are in an airport traffic pattern within one half mile of the runway, you may operate an airplane, powered parachute or weight-shift-control aircraft clear of clouds.

The exception is narrower than hangar talk makes it. Only in Class G, only below 1,200 feet AGL, only within a half mile of the runway, and never below 1 mile. Its use is landing at a dark non-towered field in a mile or two of haze. It is not permission to depart into a 1 mile night and head out on course. Leave the pattern and you are back on the 3 mile row.

Night, for 91.155, is not defined in the section itself, so the general definition in 14 CFR 1.1 applies: the time between the end of evening civil twilight and the beginning of morning civil twilight. That is a different window from the one 61.57 uses for night passenger currency, which Pilot currency requirements covers.

Surface areas add a ceiling rule and a ground visibility rule

Everything above is about flight visibility and distance from clouds. Two more paragraphs of 91.155 apply only inside controlled airspace that reaches the ground around an airport, meaning the surface areas of Class B, C, D and E.

Paragraph 91.155(c) bars VFR flight beneath the ceiling within the lateral boundaries of controlled airspace designated to the surface for an airport when the ceiling is less than 1,000 feet. The reported ceiling, not your estimate from the cockpit, is the trigger. Under 14 CFR 1.1 a ceiling is the lowest broken, overcast or obscuration layer not classified as thin or partial; a scattered layer at 600 feet is not a ceiling and does not invoke this paragraph.

Paragraph 91.155(d) bars a VFR takeoff, landing or entry into the traffic pattern within those surface areas unless ground visibility at that airport is at least 3 statute miles, or, if ground visibility is not reported there, unless flight visibility during takeoff, landing or pattern work is at least 3 statute miles. Ground visibility is what the National Weather Service or an accredited observer reports (14 CFR 1.1), so at a field with a reporting station the reported value is the one that counts. Only when there is no report does your own estimate come into it.

Both rules say "except as provided in 91.157". That is special VFR. Under 14 CFR 91.157, SVFR needs an ATC clearance, clear of clouds, flight visibility of at least 1 statute mile, and ground visibility of at least 1 statute mile to take off or land (flight visibility, if none is reported), within the lateral boundaries of a surface area and below 10,000 feet MSL. Between sunset and sunrise the airplane pilot must meet the instrument-flight requirements of Part 61 and the aircraft must be equipped under 91.205(d). Some airports bar fixed-wing SVFR altogether; sectional charts mark them "NO SVFR" above the airport name, per the FAA Aeronautical Chart Users' Guide (effective July 9, 2026).

How this differs from the flight categories on a weather map

The colors on a weather map (VFR, MVFR, IFR, LIFR) classify a reported ceiling and visibility at one station, and they are not regulations. The thresholds come from AIM 7-1-7 and are worked through in Flight categories explained. The 91.155 minimums depend on where you are, how high you are and what time it is, none of which the dot on the map knows.

The two systems line up at one point. The IFR category begins below a 1,000 foot ceiling or below 3 miles, and those are the figures 91.155(c) and (d) use for surface areas. Everywhere else they diverge. An airport reporting 2 miles under scattered clouds is colored IFR but, if it sits in Class G by day, it is above the 1 mile airplane minimum. A field reporting 10 miles and a 3,400 foot overcast is colored VFR, but a pilot cruising at 3,000 feet AGL beneath that deck in Class E is only 400 feet below it and in violation.

Use the category as a reason to open the METAR. Use 91.155 to decide what you may do once you have read it.

A way to remember it

The following is a memory aid and nothing more; the regulation is the table above.

In Class C, Class D and Class E below 10,000 feet, it is "3-152": 3 miles, 1,000 above, 500 below, 2,000 horizontal. Class B is easier. ATC is separating everyone, so the cloud clearance drops to clear of clouds, the phrase AIM 3-2-3 uses. At or above 10,000 feet MSL (and, in Class G, also more than 1,200 feet AGL) everything grows to "5-111": 5 miles, 1,000 above, 1,000 below, 1 mile horizontal.

Class G by day is the forgiving one. At 1,200 feet AGL or less it is 1 mile and clear of clouds; higher, it keeps the 1 mile but adds the 152 cloud clearance. At night G borrows the Class E rule, 3-152, with the single pattern exception in 91.155(b)(2).

So: 3-152 in controlled airspace, 5-111 high, 1 and clear low in G by day, and night turns G into E. Then read the table anyway, because the shape leaves out the surface-area rules in (c) and (d).

Worked example: legal in Class G, not in Class E

Suppose it is a hazy July afternoon over flat farmland. Flight visibility is 2 statute miles. You are cruising at 1,000 feet AGL with no cloud near you, and the sectional shows no shading for the first 15 miles of your route, so the Class E floor is 1,200 feet AGL and you are in Class G. By day, at or below 1,200 feet AGL, the row is 1 statute mile and clear of clouds. At 2 miles you are legal, with a mile in hand.

Fifteen miles along, the chart shows a soft magenta border. On the shaded side the Class E floor drops to 700 feet AGL. Hold 1,000 feet AGL across it and you are in Class E below 10,000 feet MSL, where the row is 3 statute miles and 500/1,000/2,000. At 2 miles you are a full mile short, in violation from the moment you crossed the shading, with nothing in the airplane changing.

Two of the three ways out are poor. Descending to 650 feet AGL to stay under the floor keeps you legal and puts you at tower height in 2 miles of haze. Pressing on at 2 miles is the violation. The third is the one the regulation is quietly recommending: 2 miles was never comfortable, and the boundary is where the law catches up with that judgment. Turn around, or land at the Class G field behind you, and wait.

After dark the same flight has no legal cruise segment at all. The Class G night row at or below 1,200 feet AGL is already 3 statute miles and 500/1,000/2,000.

Before a marginal VFR flight, pull up the departure and destination on FlyFren's airport pages, note which class of airspace sits over each field, and check the current METAR ceiling and ground visibility against 91.155(c) and (d). The table tells you the floor. Your personal minimums tell you where you stop.

This article is educational and is not a substitute for the current regulations, the AIM, official weather briefings, or instruction from a CFI. Check the current text at the linked sources before you rely on any detail.