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I would like to know the difference between marginal VFR (MVFR) and Special VFR (SVFR), particularly when flying in the US airspace. What does each of them mean exactly?

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  • $\begingroup$ You may be confusing two things. MVFR is a weather condition, Special VFR is a type of operation. You asked what they mean. $\endgroup$ Dec 4, 2023 at 3:53

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Marginal VFR

Straight out of the Aviation Weather Services advisory circular (AC 00-45G with changes 1 and 2):

Marginal Visual Flight Rules (MVFR) indicated on the Weather Depiction Chart represents ceiling 1,000 to 3,000 feet and/or visibility 3 to 5 statute miles and VFR operations can take place. MVFR areas are outlined with a solid line, but the area is not shaded. MVFR areas are typically shaded blue in colorized versions of the chart.

For all regulatory purposes, this has no rule changes from VFR. I believe the reason it exists is for pilots to more easily identify areas where the weather conditions are approaching IMC.

Special VFR in the US

Special VFR allows a pilot to fly within the lateral boundaries of controlled airspace to the ground with at least 1SM visibility and clear of clouds.

Special VFR is something that can be granted by ATC upon request by a pilot. It may only be granted within the lateral boundaries of controlled airspace that goes to the ground.

If the special VFR request is being made at night, the pilot and airplane must be IFR legal.

JO 7110.65Y Section Regarding Special VFR

There is no requirement that the weather conditions being reported are below basic VFR.

enter image description here

The Difference

MVFR is an advisory term.

Special VFR is an, on request by pilot only, "required weather minimums" change that may be approved by ATC.

For the purposes of special VFR in the US, here is the FAA regulation. (14 CFR 91.157)

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    $\begingroup$ Special VFR exists across the world: skybrary.aero/index.php/Special_VFR. I've never heard "marginal VFR" being used as an official term, though, so I'm guessing that's FAA specific. $\endgroup$ May 27, 2016 at 17:25
  • $\begingroup$ Just curious, where exactly in the FARs does it say that the airport must be reporting IFR conditions at the surface for Special VFR to be granted? I'm imagining a case where the conditions are just barely above IFR-- say, there is an overcast layer at 1100' AGL-- and a pilot wants to request Special VFR as a precaution in case the conditions deteriorate while he is still in the airspace in question. $\endgroup$ Dec 4, 2020 at 14:01
  • $\begingroup$ Also, there seems to be some ambiguity as to whether not Special VFR may be granted in E4 Class-E-to-Surface "extensions". For more, see related answer aviation.stackexchange.com/a/75022/34686, from the beginning of the answer through the end of the quote "Our opinion is that E4 airspace is not..." $\endgroup$ Dec 4, 2020 at 14:02
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    $\begingroup$ From an ATC perspective, MVFR conditions (ceiling 5000 or below, visibility 5SM or below) are one of the triggers for soliciting PIREPs. But that isn't a regulatory thing, just part of our orders. $\endgroup$
    – randomhead
    Mar 2, 2021 at 0:33
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    $\begingroup$ In one sentence, then, MVFR is a description of weather conditions, while SVFR refers to a type of operation, yes? $\endgroup$
    – Ralph J
    Dec 3, 2023 at 20:03
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enter image description here

source: pilotinstitute.com

To the right side on this chart is ceilings. No matter the visibility can still be MVFR, IFR or low IFR conditions. SVFR clearance can be given at or above but not below 1sm and is required if ceilings are at or below 3000ft

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    $\begingroup$ Welcome to aviation.stackexchange.com! I've added a cropped version of the screenshot you posted as a second answer to this answer and removed the other answer. Please note it is possible to edit answers and questions after you have posted them. If you have some time, please take the tour to see how this website and its community work. $\endgroup$
    – DeltaLima
    Dec 3, 2023 at 21:41
  • $\begingroup$ Re "SVFR clearance ... is required if ceilings are at or below 3000ft" -- umm, 1) I assume that "SVFR clearance .. is required" is shorthand for "VFR operations without a SVFR clearance are prohibited". 2) shouldn't that be 1000' not 3000'? 3) shouldn't that only apply to airspace that is "beneath (a) ceiling... within the lateral boundaries of controlled airspace designated to the surface for an airport"? I.e., for example, not in Class G airspace! See FAR 91.155(c) law.cornell.edu/cfr/text/14/91.155 $\endgroup$ Dec 4, 2023 at 0:07
  • $\begingroup$ The OP doesn't ask for weather differences. He asks what they mean. $\endgroup$ Dec 4, 2023 at 3:51

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