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This question is not about how to decode METARs or what software or tools can be used to decode METARs. It is about why we are still using METARs today.

Given that we have smartphones with video messaging capability, cloud services with machine learning today, I struggle to understand why we are still reading METARs:

  • It is difficult to read. Sure it is not hard to learn, but the fact that you have to learn it means it's not intuitive
  • It is designed at an age when text are transmitted by telegraph and every character counts
  • It is trivial to program a parser and render more friendly messages

For me I always feel that METARs are meant for machines; there has got to be something better for pilots which happens to be human. Instead of having this on my flight plan:

KSFO 111456Z 16015KT 9SM RA FEW012 SCT030 OVC070...

Why not just:

Station: KSFO

Time: Mar 11 14:56 UTC

Wind: 160 degrees, 15 knots

Visibility: 9 statue miles

Weather condition: rain

Clouds: few at 1,200 feet; scattered at 3,000 feet; overcast at 7,000 feet

...

The problem is not about decoding them. Most pilots can read them, and by the time a new pilot completes his PPL training he should have no trouble reading either. The point is everybody around the world is reading them, today, in the 21st century!

I don't know if I'm the only one, but processing the METAR string during flight prep takes a couple of instruction cycles away from my brain (and I have a tendency to check whether the software got it right if I happen to be using one, so I will be processing it anyway, which is a good habit I suppose). I am sure some of that brain power can be better spent somewhere else: reading section charts, route planning, picking an alternate, etc. Scaling this to the global scale? It means every pilot is paying more attention to other things, as opposed to reading coded weather strings which really is the job of a machine. The result? Better flight safely.

So, why haven't we began the move?

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  • $\begingroup$ it's a hole in the market, a METAR parsing app. $\endgroup$
    – ratchet freak
    Mar 11, 2016 at 15:54
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    $\begingroup$ Its a hold-over from its introduction in 1968 as a way to transmit a lot of information in a compact, semi-readable form. There are a lot of apps/websites that automatically translate the METAR/TAF information for you, even convert from UTC to local. $\endgroup$
    – Ron Beyer
    Mar 11, 2016 at 15:57
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    $\begingroup$ Because aviation regulations move at the speed of government... $\endgroup$
    – reirab
    Mar 11, 2016 at 15:59
  • $\begingroup$ everybody around the world is reading them, today does not sound like a compelling reason to change something designed for people who understand them. Do you suggest that every industry should talk in a way that "everybody around the world" can understand? $\endgroup$
    – Simon
    Mar 11, 2016 at 18:34
  • $\begingroup$ Personally, I find coded METARs far easier to read and understand than de-coded ones. I can scan the code faster, it is standardized, and I find it easier to parse. Seeing SCT008 tells me exactly what I need to know faster than scanning through a column of decoded text to find Clouds: Scattered at 800 feet above field elevation, or whatever the decoder might choose to parse the information as. When given the option of having a coded or a decoded METAR, which is a widely available option, I prefer the coded version. $\endgroup$
    – J W
    Mar 11, 2016 at 18:59

4 Answers 4

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One use case where the compact METAR format is tough to beat is rapidly scanning meteorological trends. For that purpose, METARs are user friendly in the sense that they are expert friendly.

For example, a friend invited me to fly with him today on an Angel Flight mission that would have required a landing at Nashville. We had to scrub because the weather is unfavorable and not getting any better according to the TAF and ADDS METAR Data:

Data at: 1616 UTC 11 Mar 2016
KBNA 111553Z 36006KT 1SM R02L/4000V6000FT -DZ BR OVC005 14/12 A3024 RMK AO2 DZB51 SLP239 P0000 T01390122 $
KBNA 111541Z 35005KT 1SM BR OVC005 14/12 A3024 RMK AO2 SFC VIS 1 1/2 $
KBNA 111527Z 01006KT 2SM BR OVC005 14/12 A3022 RMK AO2 SFC VIS 2 1/2 $
KBNA 111453Z 02008KT 3SM BR OVC005 14/12 A3021 RMK AO2 SLP227 T01390122 53015 $
KBNA 111451Z 02007KT 3SM BR OVC005 14/12 A3021 RMK AO2 $
KBNA 111434Z 01007KT 2SM BR OVC004 14/12 A3020 RMK AO2 $
KBNA 111353Z 02007KT 5SM BR OVC004 14/12 A3019 RMK AO2 SLP219 T01390122 $

A subsecond scan confirms that the low overcast ceiling is stuck at four to five hundred feet AGL for the past several hours. Try outdoing that using the same information in decoded METAR format.

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    $\begingroup$ It also says "$ FIXME . . . . $ FXME . . . . $ Yeah guys it's cool, just ignore my maintenance requests . . . . $ You'll regret this later when I say sky clear winds calm and it's actually a hurricane . . . . " :-) $\endgroup$
    – voretaq7
    Mar 11, 2016 at 16:51
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If it ain't broke...

For what its worth many new aviation apps like ForeFlight and the such display the information in user friendly formats.

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(source)

To be honest I have not decoded a METAR in some time. You are correct that the system comes from a time when transmission bandwidth was not what it is today. Keep in mind things in aviation are slow to change and many other nations also report weather in the METAR format so its useful to know how to read one if you fly abroad where they don't have the kind of infrastructure and applications we have available here in the US. Since official bodies like NOAA and the FAA broadcast METARS its far easier for a company like ForeFlight to parse and display what they can already get than try to make the government change the format.

I would love to see a broadcast of the METAR data in easy to read JSON format....

There are some packages out there for dealing with them in software if you need to.

There is also something to be said for a format that can easily be transmitted over various communication mediums. While morse code is not that popular anymore and most things are broadcast digitally the METAR format would still allow the information to be transmitted as is, in the event one of the more modern systems failed.

Since the question has been edited a bit ill expand my answer to reflect. There really is no reason to change the format since most places you get the METAR from decode it for you anyway these days. While it has been pointed out there are some quick things that can be determined from reading them in their current format there is no information that is planed to be added to them so there is no reason to change (or expand) the format. A great deal of infrastructure exists around producing and decoding them as is, which would be a large task to overhaul and in the end produce nothing different than what exists now.

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Because the METAR format is standardized and a large number of systems know how to read and process them. Lots of applications consume METAR data, from weather websites to ACARS terminals in cockpits to pilots' brains. An application can read in METAR data from many stations and use it to produce, say, a map of winds across a region or a graph of temperatures over time.

This all works because everyone has a common understanding of the format, and there are a number of code libraries for major programming languages that assist in generating and parsing the METAR format. If you change the format to be human readable, all of that breaks. As with many popular standards, changing it would require the immediate global cooperation of everyone at once.

It makes far more sense to keep the METAR format as it is (or to extend it with new elements to accommodate new reporting needs) and build tools to present the information in user friendly ways, as ForeFlight and many others do.

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Other answers have addressed some of the reasons why the METAR transmission format should stick around. I'll add that there is a lot of machinery in place that would be expensive to replace in order to make such a change, so it wouldn't happen even if we wanted it to.

If something was going to change, it could be to eliminate the testing requirement that all new pilots are able to read and interpret METARs. As has been pointed out, there are many applications both for devices and on the web that can translate them for you, including aviationweather.gov. So it's dubious reasoning to assert that a person cannot be a competent pilot unless they can interpret a METAR without assistance.

Useful skills should be trained, but only skills and knowledge required to be competent should be tested.

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