§ 91.155 Basic VFR weather minimums.

Section 91.155 sets basic VFR weather minimums — the visibility and cloud clearance values required to operate VFR. Every pilot must memorize this table. It is among the most-tested regs on every checkride.

Class A: No VFR. Period. Class A is IFR-only.

Class B (above 10,000 MSL excluded): 3 SM visibility, clear of clouds. No specific cloud-clearance dimensions — just remain visually clear.

Class C, D, E (below 10,000 MSL): 3 SM visibility, 500 below, 1,000 above, 2,000 horizontal from clouds.

Class E above 10,000 MSL (and above 1,200 AGL in Class G above 10,000 MSL): 5 SM visibility, 1,000 below, 1,000 above, 1 SM horizontal from clouds (the '5-1-1-1' rule).

Class G — below 1,200 AGL, daytime: 1 SM visibility, clear of clouds. (The '1-clear of clouds' rule that lets you scud-run legally.)

Class G — below 1,200 AGL, nighttime: 3 SM visibility, 500 below, 1,000 above, 2,000 horizontal. Night Class G is treated the same as Class E surface.

Class G — above 1,200 AGL but below 10,000 MSL, daytime: 1 SM visibility, 500 below, 1,000 above, 2,000 horizontal.

Class G — above 1,200 AGL but below 10,000 MSL, nighttime: 3 SM visibility, 500 below, 1,000 above, 2,000 horizontal.

Class G — above 10,000 MSL: 5 SM visibility, 1,000 below, 1,000 above, 1 SM horizontal.

Why the 10,000 MSL break: Above 10,000 MSL the speed limit goes away (no more 250 KIAS). Faster aircraft need more visibility and bigger cloud-clearance margins to see-and-avoid effectively. The 5-1-1-1 rule reflects that.

The 1,200 AGL break for Class G: Below 1,200 AGL is the 'low-altitude maneuvering' zone where aircraft are typically engaged in pattern flying, ag operations, helicopter EMS, etc. The reg cuts the pilot a break on cloud clearance there during daylight because aircraft below 1,200 AGL are typically operating at a known site and can see-and-avoid at closer ranges. Night flips back to the 3-152 rule because visual reference is degraded.

Special VFR (§ 91.157): Allows lower visibility VFR in controlled airspace surface area with an ATC clearance. See § 91.157 research notes.

Reference: AIM 3-1 on airspace fundamentals; FAA-H-8083-25 (PHAK) Chapter 15 on airspace including VFR weather minimums.

Basic VFR Weather Minimums — The Table Every Pilot Memorizes

If there's one regulation you'll be quizzed on more than any other in your training, it's this one. § 91.155 is the cloud-clearance and visibility table — the numbers that decide whether your VFR flight is legal or not. Every CFI teaches it. Every DPE asks about it. And every pilot eventually memorizes some version of it.

Here's the table, straight from the reg:

Two patterns are worth seeing inside the table:

• The 10,000 MSL break. Above 10,000 MSL the 250 KIAS speed limit goes away. Faster traffic means you need more room to see and avoid — so visibility jumps to 5 SM and horizontal cloud clearance jumps to 1 statute mile. The "5-1-1-1" you'll hear instructors call out.
• The 1,200 AGL break in Class G. Below 1,200 AGL during the day, Class G drops to 1 SM and clear of clouds. That's the regulatory relief for low-altitude operations near uncontrolled fields — pattern work, ag flying, helicopter EMS. At night, that relief disappears: you're back to 3 SM and the standard 500/1,000/2,000 split.

Some CFIs teach "3-152" or "5-111." Others draw the table cold. Pick whatever sticks — but memorize the actual numbers, not just the chant. A DPE will phrase the question in a way the mnemonic doesn't answer. If you only know "3-152," you'll freeze the moment they say "10,500 MSL." Know the table.

What an Examiner Asks About § 91.155

This reg shows up on every private, commercial, and CFI checkride — and usually more than once. Examiners aren't testing whether you can sing the mnemonic. They're testing whether you can pull the right row out of the table when the scenario changes mid-question.

Common questions, roughly in the order they come up:

• "What are the VFR weather minimums for Class E below 10,000 MSL?" 3 statute miles visibility, 500 below, 1,000 above, 2,000 horizontal. The bread-and-butter answer. Say it cleanly.
• "What changes at night?" Nothing in Class B, C, D, or E. Class G is where night matters — below 1,200 AGL it goes from 1 SM clear-of-clouds (day) to 3 SM and the standard cloud-clearance split (night). Same jump above 1,200 AGL: 1 SM day, 3 SM night.
• "You're VFR at 10,500 MSL. What are your minimums?" The altitude is the trap. 10,500 is above 10,000 MSL, so you're in the 5-1-1-1 column — 5 SM, 1,000 below, 1,000 above, 1 statute mile horizontal — regardless of whether you're in Class E or Class G up there.
• "What are your minimums in Class G during the day at 1,000 AGL?" 1 statute mile and clear of clouds. The most permissive line in the entire table — and the one that makes scud-running technically legal and operationally stupid.
• "You're approaching an uncontrolled field. The surface area is Class E. What's the ground visibility minimum to land VFR?" Trick question, but a fair one. § 91.155(d) requires ground visibility of at least 3 SM at airports with a Class B, C, D, or E surface area — even if the field is uncontrolled. If ground vis isn't reported, flight visibility in the pattern has to be at least 3 SM. Special VFR (§ 91.157) is the exception, not the rule.

Examiners pass students who can switch rows in the table without losing their place. The minimums aren't memory trivia — they're the legal floor of the flight you're about to fly.

A Real Decision, Under § 91.155

You're 20 miles out, VFR, descending toward your destination. The most recent METAR was 35 minutes ago: 3 SM visibility, scattered at 2,500, broken at 3,500. Legal on paper. But what you actually see out the windshield is haze that's thicker than what the METAR is selling, and the broken layer looks lower than 3,500. Here's what § 91.155 makes you do — and what being a competent PIC adds on top:

The reg pulls you to: Maintain 3 SM flight visibility and the 500/1,000/2,000 cloud clearance for Class E below 10,000 MSL. If you're landing at a field inside a Class E surface area, § 91.155(d) says ground visibility there has to be 3 SM — or if it isn't reported, your flight visibility in the pattern does. If the ceiling is less than 1,000 feet over the surface of controlled airspace designated to the surface, § 91.155(c) blocks you from operating beneath it under VFR at all. Your options at that point are Special VFR (§ 91.157) with an ATC clearance, an IFR clearance if you're rated and equipped, or a divert.

What competent adds: Trust your eyes over a 35-minute-old report. If what you see doesn't match what's reported, the report is stale — request an updated one or call the FBO. Ask yourself whether you can maintain those minimums for the entire approach, not just right now. If the haze is closing behind you and the ceiling is dropping, "legal at the moment" doesn't help you on the next mile. Set a personal minimum that sits above the reg's floor — and brief the divert before you're inside 10 miles. Most VFR-into-IMC accidents happen at or near legal minimums, where the pilot believed the rule was the standard. The rule is the floor. The standard is whether you'd be comfortable flying this approach with your family in the back.

The reg is what they'll cite if you bust it. The competent layer is what keeps you out of the NTSB report.