How to read a METAR in the US and Canada

Pull up the weather for Boston and the METAR just keeps going:

METAR KBOS 080854Z 32014KT 4SM -RA BR BKN007 OVC018 09/08 A2963 RMK AO2 RAB0758 SLP032 P0008 60008 T00890078 53004 $

That's Boston Logan at 0854 UTC on 8 November 2026. The first half is one line of code describing the airport's weather at that moment: wind, visibility, weather, sky condition, temperature, dew point and altimeter setting. Everything after RMK is remarks, and that's where North American reports get chatty.

The basic layout is the same as everyone else's. The units are different, though, and the US and Canada each have habits of their own. We'll work through real reports from Boston, Santa Rosa and Toronto and point out each US and Canadian difference as we reach it. To decode a live report as you read, type its ICAO code into the free METAR and TAF decoder.

Example: Boston in rain#

Here's the body of the report:

And the remarks:

Say it out loud and it's northwest at 14, 4 miles in light rain and mist, ceiling 700 broken, 1,800 overcast, 9 and 8, 29.63. Honestly, we'd spend that morning on ground school.

The order of the groups in a METAR#

Boston's report used most of the groups. Here's the full set, in the order they always come:

1. Report type (METAR or SPECI) and station
2. Date and time (UTC)
3. Report modifier: AUTO, or a correction
4. Wind
5. Visibility in statute miles, then runway visual range if it is low
6. Present weather
7. Sky condition
8. Temperature and dew point
9. Altimeter setting
10. RMK, then the remarks

Any group that doesn't apply is left out, which is why a quiet afternoon's report can be half the length of Boston's.

What each group in the body means#

Time and modifiers#

Times are UTC, marked Z. A routine US METAR is observed a few minutes before the hour and carries that time. That's why Boston's 0900 report reads 0854Z and Farmingdale's reads 0853Z. Canada takes its METARs every hour on the hour at more than 200 aerodromes, and they carry the official on-the-hour time (TC AIM).

AUTO means fully automated, with no human involved. In the US, a report without AUTO is either a manual observation or an automated one with an observer signed on to check it and add to it (JO 7900.5E). Farmingdale, New York, showed both on 8 November. Its 0953Z report says AUTO and its 1253Z report doesn't. Both carry AO2, which describes the station's equipment, not whether anyone was watching it.

The two countries mark corrections differently. The US uses COR, and never alongside AUTO, since a correction means an observer is involved. Canada uses CCA for the first correction and CCB for the second, and is happy to print AUTO CCA together.

Wind#

32014KT is from 320 degrees true at 14 knots. Both countries give METAR wind in degrees true. So before you work out a crosswind, check whether the runway heading in front of you is true or magnetic. It's a small thing that's easy to skip when you're in a hurry. The crosswind clock rule guide shows the conversion.

Gusts and variable winds are where the two countries part company:

Canada's lower gust threshold is how Vancouver came to report 19009G16KT, 9 knots gusting 16, on 8 November. Calm is 00000KT in both countries.

Gusts turn up in the remarks too. Here's Boston again at 2254Z the same day, with the rain gone and the wind up:

METAR KBOS 082254Z 26014G29KT 10SM FEW044 SCT200 12/04 A2968 RMK AO2 PK WND 28029/2245 SLP050 T01170039 $

PK WND 28029/2245 is the peak wind since the last METAR: 29 knots from 280 degrees at 2245 UTC. US automated stations add it when the peak goes above 25 knots. When you use the crosswind calculator, put in the gust figure, not the mean. You'll be landing in the gusts as well as the average.

Visibility and RVR#

Visibility is in statute miles, with SM on the end. A fraction sits after a space from the whole miles, so Boston's 0254Z report read 1 1/2SM +RA BR. US automated stations write M for less than, as in M1/4SM. They also top out at 10 miles, and manual reports go up in 5-mile steps above 15. Canada has no maximum at all, which is why Vancouver so often reports 30SM.

In both countries, runway visual range is added when visibility is 1 mile or less, or RVR is 6,000 ft or less. It's given in feet. R04R/P6000FT in Boston's 0819Z special on 8 November means runway 04 right, more than 6,000 ft. Canada adds a trend after a slash: /U up, /D down, /N no change.

Present weather#

This is the part that looks most like alphabet soup, but it only has three pieces. Intensity or proximity comes first, then a descriptor, then the weather itself:

• - light, no sign moderate, + heavy. Intensity describes the precipitation, so -TSRA is a thunderstorm with light rain. VC means in the vicinity rather than at the station. In the US that's 5 to 10 statute miles away, or up to 10 for precipitation, as in VCSH (JO 7900.5E). In Canada it's within 5 statute miles (TC AIM).
• Descriptors: SH showers, TS thunderstorm, FZ freezing, MI shallow, BC patches, PR partial, BL blowing, DR drifting.
• Precipitation: RA rain, DZ drizzle, SN snow, GR hail, GS small hail or snow pellets, PL ice pellets, UP unknown precipitation from an automated station.
• Obscuration: BR mist, FG fog, HZ haze, FU smoke.

In both countries FG means visibility under 5/8 mile and BR means 5/8 mile or more. The US also only uses BR below 7 miles (JO 7900.5E).

Sky condition#

Cloud comes as FEW, SCT, BKN or OVC (1 to 2, 3 to 4, 5 to 7 and 8 eighths), followed by the base in hundreds of feet above ground. CB or TCU is tacked onto the layer, as in OVC010CB.

The ceiling is the lowest layer reported broken or overcast, or the vertical visibility (VV002) into something that hides the whole sky. Boston's ceiling above was 700 ft, not 1,800 ft.

Both countries add the amounts up from the surface, so each layer's figure includes all the cloud beneath it. A layer reported BKN can be thin on its own. Only Canadian remarks split the total out layer by layer, so Canada is the only place you can actually see which layers are thin (more on that under Canadian remarks below).

The US has two codes for a clear sky, and they don't promise the same thing. SKC comes from a human observer and means no cloud. CLR comes from an automated station and only means nothing was detected at or below 12,000 ft. When Farmingdale reported 10SM CLR on a gusty afternoon, it said nothing about cloud above that height. Canadian automated stations report CLR when nothing is detected below 25,000 ft, though some private systems only see to 10,000 ft.

Temperature, dew point and altimeter#

09/08 is 9°C and 8°C, rounded to the nearest degree. M means minus, as in 03/M02. A spread of a degree or two at dusk is a warning of mist and fog, and it's the number we'd look at twice before an evening flight.

A2963 is 29.63 inches of mercury: put a decimal point after the second digit. That's the number for the Kollsman window. Don't mix it up with SLP in the remarks, which is sea-level pressure in hectopascals. SLP is worked out from actual temperatures rather than the standard atmosphere, so it won't convert neatly into your altimeter setting (TC AIM).

Example: Santa Rosa going into fog#

This is the one we'd want every student to see. Three reports from Santa Rosa, California, an hour apart on a still night on 8 November (UTC), running from about 10 pm to midnight local time:

METAR KSTS 080553Z AUTO 00000KT 8SM CLR 11/10 A3013 RMK AO2 SLP197 T01060100 10228 20094 51009

METAR KSTS 080653Z AUTO 00000KT 7SM BKN004 10/09 A3013 RMK AO2 SLP196 T01000094

METAR KSTS 080753Z AUTO 00000KT 1/4SM FG VV002 08/08 A3013 RMK AO2 SLP198 T00830083 402500033

At 0553Z it's calm, with 8 miles and nothing detected up to 12,000 ft. Lovely, at first glance. But the T group gives 10.6°C and a dew point of 10.0°C, a spread of six tenths of a degree.

An hour later, at 0653Z, it's still calm, and a broken layer has formed at 400 ft. That's now the ceiling.

By 0753Z it's a quarter of a mile in fog. VV002 means the sky is hidden and the observer (here a sensor) can see 200 ft up into it, so the ceiling is 200 ft. T00830083 puts temperature and dew point both at 8.3°C.

So the airport went from a clear night to a quarter of a mile in two hours. The first report looked flyable on every main figure. The clues were the narrow spread and the calm wind, and both were there from the start.

The remarks section#

US remarks are mostly machine-generated, and you don't need to memorise them all. These are the ones you'll meet most often:

Canadian remarks: cloud by layer#

Canadian remarks open with the cloud type and opacity of each layer, in eighths, and this is where they get properly useful. Here's Toronto Pearson at 0200Z on 9 November:

METAR CYYZ 090200Z 26014KT 12SM -RA FEW025 BKN052 OVC095 09/06 A2973 RMK SC2SC5AC1 SLP073

SC2SC5AC1 reads stratocumulus 2/8, stratocumulus 5/8, altocumulus 1/8. Add them up as you climb and you get the amounts in the body: 2 is FEW, 2 + 5 = 7 is BKN, and 7 + 1 = 8 is OVC. So that "overcast" at 9,500 ft is, on its own, one eighth of altocumulus. SLP073 is 1007.3 hPa and is the last mandatory field.

Canada also adds a density altitude remark, such as DENSITY ALT 500FT in Vancouver's 0200Z report on 8 November, when density altitude is 200 ft or more above the aerodrome elevation. Before a summer departure, check it against the density altitude calculator. In either country, PRESFR or PRESRR is your cue to get a fresh altimeter setting before trusting the one you have. Toronto's 1700Z report on 8 November carried PRESFR.

What a METAR does not tell you#

• What happens next. It's a single observation. For the next few hours you need the TAF, and our TAF guide works through one.
• What it's like away from the field. A ridge 15 miles away can be in cloud while the METAR reads 10SM CLR.
• Proof that an automated station saw everything. CLR only goes as high as the sensor reaches, and $ means the station knows something is wrong. Canadian automated stations outside lightning detection coverage can't report thunderstorms at all (TC AIM).
• Whether the flight is legal. Read the METAR alongside the forecast, NOTAMs and an official briefing: Flight Service in the US, NAV CANADA in Canada.

Decoding live reports#

The METAR and TAF decoder shows the latest report for any ICAO code in plain English, along with the last six hours of reports and the TAF drawn as a VFR and IFR timeline. If your strip has no weather station, the airfield pages show the latest METAR from the nearest airport that has one, with its distance in nautical miles, next to runways and frequencies.

The habit we'd recommend is to decode your home field's report over breakfast, then check your reading against the decoder. After a week or two, a report like Boston's stops looking like a wall of code.

Weather cancellations in Volanti#

If you run a club's or school's bookings, a 700 ft ceiling at 0854Z means a morning of cancellations and a few disappointed students. In Volanti, a booking cancelled for weather records the reason, and the aircraft or instructor can be held for everyone so nobody rebooks straight into the same weather. Once the hold is released, the waiting list runs again by itself. Booking and scheduling explains how it works.