METAR Study Guide

Aviation Routine Weather Report (METAR)
- Edition III -

FOREWORD

This information booklet has been designed and prepared by the Training and Education Services Branch to aid in decoding Aviation Routine Weather Reports (METAR). Its contents are in accordance with the standard coding as developed and approved by the National Weather Services Directorate of Environment Canada.
 
 

Table of Contents


Part I Aviation Routine Weather Report (METAR)

1.1 Introduction 
1.2 Symbolic Form of the METAR Code (Canada)
1.3 Detailed Decoding 
1.4 METAR Examples 
1.5 METAR Exercise 
1.6 METAR Exercise Answers 





AVIATION ROUTINE WEATHER REPORT (METAR)

1.1 Introduction 

1.1.1 The METAR Code 

The hourly code, or SA, has been used in North America for over 50 years. A different code, METAR, is used for aviation weather in the rest of the world. Canada made a commitment to produce and distribute METAR reports internationally for 31 sites commencing July 31, 1993. Further to this, Canada, the United States, and Mexico have agreed to replace the SA with METAR for aviation within North America beginning in 1996.

The purpose of this booklet is to further explain each element of the METAR and to give examples of the various codes. An exercise has been provided to reinforce one's understanding of this new code.

METAR is the name of the international meteorological code for an aviation routine weather report. METAR observations are normally taken and disseminated on the hour. A SPECI, the name of the code for an aviation selected special weather report, will be reported when weather changes of significance to aviation are observed.

In Canada, METAR and SPECI reports are not encoded by the observer, but are generated by computer software, based on hourly or special observations taken at either staffed or automatic sites. 

The code is composed of several groups which are always in the same relative position to one another. When a weather element or phenomenon does not occur, the corresponding group (or extension) is omitted. Certain groups may be repeated.


1.1.2 National Variations 

Despite the fact that METAR is an international code, there are some national variations. For example, wind speed may be reported in different units, however the units are always appended to the values to avoid any misunderstanding.
 
 
AVIATION ROUTINE WEATHER REPORT (METAR) CANADA
METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134
METAR Message Type METAR (OR SPECI)
CYWG Winnipeg, Manitoba 4-Letter ICAO identifier
172000Z 17th day at 2000 UTC (Z) Date/Time of observation
30015G25KT Wind direction 300 degrees
true, speed 15 knots,
Gusts to 25 knots (KT)
First three digits are direction to the nearest 10 degrees true. VRB is used for variable direction, if 3 knots or less. Calm is encoded as 00000KT. Next two digits are speed, followed by gusts to report a 2-digit maximum speed. For speeds equal to or greater than 100 KTS, 3 digits are used. Units are knots (KT).
3/4SM Visibility three quarters of a statute mile (SM) Prevailing visibility is reported in statute miles and fractions. Visibility of 15+ is encoded as 15SM. Lower visibilities which are half or less of the prevailing visibility are reported in the remarks section.
R36/4000FT/D RVR for runway 36 is 4000 ft with a downward trend The 10-minute average runway visual range is reported when prevailing visibility is 1 mile or less, and/or the runway visual range is 6000 feet or less. D indicates downward trend, U upward trend, and N no change.
-SN

BLSN
 

Light snow

Blowing snow
 

Present weather is comprised of weather phenomena (precipitation, obscuration, or other) preceded by one or two qualifiers (intensity or proximity to the station and descriptor). See Code Table 4678 for a list of qualifiers and weather phenomena, and their symbols.
BKN008

OVC040
 

Broken at 800 feet
 

Overcast at 4000 feet
 

Sky cover amounts are cumulative. Therefore layer amounts include the sum of any layers below. Codes for sky cover amounts are:

SKC (sky clear)
FEW (few, <1 to 2 oktas)
SCT (scattered, 3 to 4 oktas)
BKN (broken, 5 to <8 oktas)
OVC (overcast, 8 oktas)
VV (sky obscured)

Cloud height is reported in 3 digits in hundreds of feet. CB or TCU is added as needed. Vertical visibility (VV) is reported in hundreds of feet. Partially obscured is reported as SKC ( if no cloud) or is included with the first layer.

M05/M08 Temperature -5°C
Dewpoint -8°C
Observed values with 0.5 degrees are rounded up to the next warmer degree. M signifies a negative temperature.
A2992 Altimeter setting 29.92 "A" indicates inches of mercury. Some countries use "Q" which indicates hectopascals.
REFZRA Recent freezing rain Recent weather in the period since the last routine report but not at the time of observation.
WS RWY36 Windshear Runway 36 Supplementary information on windshear (within 1600 ft AGL, provided by an aircraft along the takeoff or approach path).
RMK
SF5NS3
SLP134
Remarks:
5 oktas Stratus fractus
3 oktas Nimbostratus
Sea level pressure: 1013.4 hPa
Remarks will include in the following order: layer type and opacity in oktas; general weather remarks; and sea level pressure

1.2 Symbolic Form of the METAR Code (Canada)

METAR or SPECI CCCC YYGGggZ (AUTO) (BBB) dddffGfmfmKT dndndnVdxdxdx

VVVVSM RDRDR/VRVRVRVRFT/i orRDRDR/VRVRVRVRVVRVRVRVRFT/i w'w'

NsNsNshshshsand/orVVhshshs T'T'/T'dT'dAPHPHPHPHREw'w' WS RWYDRDR or 

WS ALL RWY RMK (Layer type and opacity) (General Remarks) SLPppp
 

Symbols shown in BOLD in the symbolic format are included verbatim as part of the message, whenever the relevant group is included in the message. All other symbols are replaced by appropriate data as applicable.


1.3 Detailed Decoding 

1.3.1 METAR (or SPECI) - Report Name 

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

The code name METAR (or SPECI), is given in the first line of text. A "SPECI" report is issued when significant changes in weather conditions occur off the hour. There is no provision in METAR for an "RS" report. 
 

METAR (or SPECI) - Report Name 

Example #1: METAR CYYZ 040600Z
An aviation weather report taken on the hour.

Example #2: SPECI CYQB 191211Z
A special aviation weather report taken at 1211 UTC.0


1.3.2 CCCC - Station Identifier 

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36RMK SF5NS3 SLP134

CCCC is the 4-letter ICAO station identifier (formed by "C" preceding the Canadian 3?letter station identifier).
CCCC - Station Identifier

Example: CYUL (Montreal/Dorval International Airport)
The 3-letter identifier is YUL; the 4-letter METAR identifier is CYUL.


1.3.3 YYGGggZ (AUTO) (BBB) - Date/Time of Observation (and Other Indicators) 

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

The date and time of observation (YYGGggZ) is included in all reports. The official time of observation (on the hour) is used for all METAR reports that do not deviate from the official time by more than 10 minutes. In SPECI reports the time refers to the time of occurrence (hours and minutes) of the change(s) which required the issue of the report.

YYGGggZ - Date/Time of Observation

(AUTO) - Automatic Station Indicator

(BBB) - Correction Indicator

Example #1: METAR CYUL 051200Z CCB 

The official time of observation was 1200 UTC, on the 5th day. This was the second correction to the 1200Z report. (The first correction to a METAR or SPECI would be denoted by CCA, the second correction to the same report by CCB, and so on.)
 

Example #2: METAR CYHZ 131600Z AUTO
This is an autostation (AWOS) report taken on the 13th day at 1600 UTC.0


1.3.4 dddffGfmfmKT - Wind 

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134 

This group reports the 2-minute mean wind direction and speed, along with gusts.

Wind direction (ddd) is always three digits, given in degrees (true) but rounded off to the nearest 10 degrees (the third digit is always a "0"). In the case of mean wind speeds of 3 knots or less and a variable direction, wind direction (ddd) is encoded as "VRB".

Wind speeds (ff) are two digits (or three digits if required), in knots.

Calm is encoded as "00000KT".

Gfmfm - Gust Information 

Gfmfm will be included if gust speeds exceed the mean speed by 10 knots or more in the 10-minute period preceding the observation. If this condition is not met, Gfmfm is omitted. G indicates gusts and fmfm is the peak gust reported, using two or three digits as required.

KT - Wind Units

In Canada and the U.S., the unit for wind speed is knots (nautical miles per hour). Other countries may use kilometres per hour (KMH), or metres per second (MPS).

dddffGfmfmKT - Wind 

example #1: 01012G23KT

Wind: 010 degrees true at 12 knots, gusting to 23 knots.

example #2: 22010KT
Wind: 220 degrees true at 10 knots.

example #3: VRB02KT
Wind direction variable with a speed of 2 knots.0


1.3.5 dndndnVdxdxdx - Variations in Wind Direction 

METAR CYWG 172000Z 30015G25KT 260V340 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

This group reports variations in wind direction. It is only included if during the 10?minute period preceding the observation the direction varies by 60 degrees or more, and the mean speed exceeds 3 knots. The two extreme directions are encoded in clockwise order.

dndndnVdxdxdx - Variations in Wind Direction

example: 060V130
The wind direction is varying from 060 degrees to 130 degrees.0


1.3.6 VVVVSM - Prevailing Visibility 

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

This group reports the prevailing visibility in statute miles and fractions. VVVV is the reported visibility and SM indicates the units are statute miles. Lower sector visibilities which are half or less of the prevailing visibility are reported as remarks at the end of the report.

In Canada and the U.S., the unit for reporting visibility is statute miles. Other countries report the visibility in metres.

VVVVSM - Prevailing Visibility

example #1: 3/4SM
The prevailing visibility is 3/4 statute miles.

example #2: 15SM... RMK VSBY N 3
The prevailing visibility is 15 statute miles... Remark: visibility north 3 statute miles.


1.3.7 RDRDR/VRVRVRVRFT/i - Runway Visual Range 

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

This group reports the 10-minute average runway visual range. It is included if the prevailing visibility is 1 statute mile or less, and/or the runway visual range is 6000 feet or less.

R, the group indicator, is followed by DRDR which is the runway designator (e.g. "06"), to which may be appended the letters "L", "C", or "R" (left, centre, or right) if there are two or more parallel runways.

VRVRVRVR is the value of RVR reported in hundreds of feet, using three or four digits. FT indicates the units for RVR are feet. "M" preceding the lowest measurable value (or "P" preceding the highest) indicates the value is beyond the instrument range.

i indicates the RVR trend. If there is a distinct upward or downward trend from the first to the second 5-minute part-period such that the RVR changes by 300 feet or more, the trend (i) is encoded "U" or "D" (upward or downward). If no distinct change is observed, the trend (i) is encoded "N". If it is not possible to determine the trend, /i is omitted.

RDRDR/VRVRVRVRVVRVRVRVRFT/i - Variations in RVR

VRVRVRVRVVRVRVRVR is used (instead of VRVRVRVR) to report the minimum and maximum one-minute mean RVR values during the 10-minute period preceding the observation, if they vary from the 10-minute mean by at least 20% (and by 150 feet).

RDRDR/VRVRVRVRFT/i - Runway Visual Range

RDRDR/VRVRVRVRVVRVRVRVRFT/i - Variations in RVR

example #1: R06R/4000FT/D
The RVR for runway 06 right is 4000 feet and the trend is downward.

example #2: R27/P6000FT/N
The RVR for runway 27 is more than 6000 feet and there is no change.

example #3: R36/1000V2400FT/U
The RVR for runway 36 is varying from 1000 feet to 2400 feet, and the trend is upward.


1.3.8 w'w' - Present Weather 

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

w'w' represents present weather, coded in accordance with WMO Code Table 4678. As many groups as necessary are included, with each group containing from 2 to 9 characters.

Present weather is comprised of weather phenomena, which may be one or more forms of precipitation, obscuration, or other phenomena. Weather phenomena are preceded by one or two qualifiers, one of which describes either the intensity or proximity to the station of the phenomena, the other of which describes the phenomena in some other manner.

QUALIFIERS 

Intensity 

(-) light (no sign) moderate (+) heavy
 

If the intensity of the phenomena being reported in a group is either light or heavy, this is indicated by the appropriate sign. No sign is included if the intensity is moderate, or when an intensity is not relevant.

If more than one type of precipitation are reported together in a group, the predominant type is given first. However, the reported intensity represents the "overall" intensity of the combined types of precipitation.

Proximity 

The Proximity qualifier VC is used in conjunction with the following phenomena:

  • SH (showers);
  • FG (fog);
  • BLSN, BLDU, BLSA (blowing snow, blowing dust, blowing sand);
  • PO (dust/sand whirls);
  • DS (duststorm), SS (sandstorm). 
VC is used if these phenomena are observed within 8 KM (5 miles), but not at the station. When VC is associated with "SH", the type and intensity of precipitation is not specified.

WMO Code Table 4678 (incorporating Canadian differences) 

Significant present weather codes.





QUALIFIER
WEATHER PHENOMENA
INTENSITY OR 
PROXIMITY
1
DESCRIPTOR

2

PRECIPITATION

3

OBSCURATION 
4
OTHER

5

Note: Precipitation
intensity refers to all forms combined.
 

- Light
 

Moderate
(no qualifier)
 

+ Heavy
 
 
 

VC In the
Vicinity
 

MI Shallow
 

BC Patches
 

PR Partial
 

DR Drifting
 

BL Blowing
 

SH Shower(s)
 

TS Thunderstorm
 

FZ Freezing
 

DZ Drizzle
 

RA Rain
 

SN Snow
 

SG Snow
Grains
 

IC Ice
Crystals
(VVVV £ 6 SM) 
 

PL Ice
Pellets
 

GR Hail
 

GS Snow
Pellets
 

UP Unknown
precipitation
(auto)

BR Mist
(VVVV 3 5/8 SM) 
 

FG Fog
(VVVV < 5/8 SM)
 

FU Smoke
(VVVV £ 6 SM) 
 

VA Volcanic
Ash
(with any visibility)
 

DU Dust
(VVVV £ 6 SM) 
 

SA Sand
(VVVV £ 6 SM) 
 

HZ Haze
(VVVV £ 6 SM) 
 

PO Dust/sand 
Whirls
(Dust Devils)
 

SQ Squalls
 

+FC Tornado or
Waterspout
 

FC Funnel Cloud
 

SS Sandstorm
(VVVV < 5/8 SM)
(+SS VVVV < 5/16 SM)
 

DS Duststorm
(VVVV < 5/8 SM)
(+DS VVVV < 5/16 SM)
 

Descriptor 

MI....SHALLOW DR....DRIFTING TS....THUNDERSTORM
BC....PATCHES BL....BLOWING FZ....FREEZING 
PR....PARTIAL SH....SHOWERS
 

No w'w' group has more than one descriptor.

The descriptors MI (shallow), BC (patches) and PR (partial) are used only in combination with the letter abbreviation FG (fog), e.g. "MIFG".

The descriptors DR (drifting) and BL (blowing) are used only in combination with SN (snow), DU (dust) and SA (sand). Drifting is used if the snow, dust or sand is raised less than two metres above ground; if two metres or more, blowing is used.

If blowing snow (BLSN) and snow (SN) are occurring together, both are reported but in separate w'w' groups, e.g. "SN BLSN".

SH (shower) is used only in combination with precipitation types RA (rain), SN (snow), PE (ice pellets), GR (hail) and GS (snow pellets) if occurring at the time of observation, e.g. "SHPE" or "-SHRAGR".

TS (thunderstorm) is either reported alone or in combination with one or more of the precipitation types. The end of a thunderstorm is the time at which the last thunder was heard, followed by a 15-minute period with no further thunder.

(Note: TS and SH are not used together, since w'w' groups can have only one descriptor.)

FZ (freezing) is used only in combination with the weather types DZ (drizzle), RA (rain) and FG (fog).


WEATHER PHENOMENA

Different forms of precipitation are combined in one group, the predominant form being reported first. The intensity qualifier selected represents the overall intensity of the entire group, not just one component of the group. The one exception is freezing precipitation (FZRA or FZDZ), which is always reported in a separate w'w' group.

Obstructions to Vision are generally reported if the prevailing visibility is six miles or less, with some exceptions. 

Any obscuration occurring simultaneously with one or more forms of precipitation is reported in a separate w'w' group. Other phenomena are also reported in separate groups.

PRECIPITATION

        RA....RAIN                                    DZ....DRIZZLE
        SN....SNOW                                    SG....SNOW GRAINS
        PE....ICE PELLETS                             GR....HAIL
        GS....SNOW PELLETS                            IC.....ICE CRYSTALS
        UP....UNKNOWN PCPN (AUTO)
                
OBSCURATION

        BR....MIST                                      FU....SMOKE
        FG....FOG                                       HZ....HAZE
        SA....SAND                                      DU....DUST
        VA....VOLCANIC ASH

OTHER PHENOMENA

        PO....DUST/SAND WHIRLS                          SQ....SQUALLS
        SS.....SANDSTORM                                DS....DUSTSTORM
        +FC....TORNADO/WATERSPOUT                       FC....FUNNEL CLOUD
                 (individual type reported in remarks)            (type reported in remarks)
w'w' - Present Weather

example #1: -RADZ BR
Light rain and drizzle with mist (visibility 3 5/8 mile) are occurring.

example #2: -SN
Light snow is occurring.

example #3: FZFG

Freezing fog (visibility < 5/8 mile), whether depositing rime ice or not, is occurring.

example #4: TSRA
A thunderstorm with moderate rain is occurring. (Character of precipitation is not specified.)

example #5: VCSH
A shower is in the vicinity of the station, but is not occurring at the station. (The type and intensity of precipitation are not specified.)

example #6: -SN BLSN
Light snow and blowing snow are occurring.

example #7: +BLSN
Heavy blowing snow is occurring. (Snow might be occurring along with the blowing snow, even though it has not been reported. In blowing snow conditions, if an observer is not certain that it is snowing, only blowing snow is to be reported.)

example #8: TSRAGR +FC...RMK TORNADO
A thunderstorm with moderate rain and hail, and a tornado (based on the remark) are occurring.


1.3.9 NsNsNshshshs - Layers Aloft

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

This group is used to report sky condition for layers aloft. NsNsNs symbolizes the layer coverage, and hshshs represents the height of the layer above station elevation. Summation amount (the cumulative portion covered) is used to determine the coverage symbol.

Cloud amounts, NsNsNs, are encoded as follows:

  • SKC "sky clear" - no cloud present
  • FEW "few" - <1/8 to 2/8 summation amount
  • SCT "scattered" - 3/8 to 4/8 summation amount
  • BKN "broken" - 5/8 to <8/8 summation amount
  • OVC "overcast" - 8/8 summation amount
  • CLR "clear" - clear below 10,000 ft as interpreted by an autostation 
There is no provision in METAR for qualifying the layer coverage as "thin".

There is no provision in METAR for reporting partially obscured conditions. Therefore, if no cloud is present, "?X" is reported as SKC; if one or more layers aloft are present along with "-X", its amount is included in the summation amount of the first layer aloft.

A cloud ceiling is said to exist at the height of the first layer for which a coverage symbol of BKN or OVC is reported. The existence of a vertical visibility reported in the VVhshshs group constitutes an obscured ceiling.

hshshs represents the height of the layer above station elevation in increments of 30 metres (100 feet) to a height of 3,000 metres (10,000 feet), thereafter in increments of 300 metres (1,000 feet).

Significant convective clouds (CB or TCU only), if observed, are identified by the letter abbreviations CB (Cumulonimbus) or TCU (Towering Cumulus) appended to the cloud group without a space, e.g. "SCT025TCU".

VVhshshs - Vertical Visibility

METAR CYYT 081100Z 00000KT 0SM FG VV000 07/07 A3019 RMK F8 SLP224

This group is reported when the sky is obscured. VV is the group indicator, and hshshs is the vertical visibility in units of 30 metres (hundreds of feet).
 

hshshs - Examples of Encoding
HEIGHT METAR CODE
100 ft (30 metres) 001
450 ft (135 metres) 004
2,700 ft (810 metres) 027
12,600 ft (3,780 metres) 1300


International Reporting Variations 

The WMO standard is somewhat different than Canadian standards for reporting of cloud layers. The criteria below is given for reference only and is not applicable to Canadian reporting stations.

The selection of layers or masses of cloud reported shall be made in accordance with the following criteria:

1st group: the lowest individual layer (mass) of any amount, to be reported as FEW, SCT, BKN or OVC

2nd group: the next individual layer (mass) covering more than two oktas, to be reported as SCT, BKN or OVC

3rd group: the next higher individual layer (mass) covering more than four oktas, to be reported as BKN or OVC

Additional groups: significant convective clouds (CB or TCU) when observed and not already reported in one of the three groups above.
 

CAVOK This term will not be used in Canada.

Reports from other countries may use the term CAVOK. This would imply the following conditions are occurring simultaneously at the time of observation:

  1. Visibility: 10 km or more;
  2. No cloud below 1500 metres (5000 ft) or below the highest minimum sector altitude, whichever is greater, and no Cumulonimbus;
  3. No significant weather phenomena (see Code Table 4678).

1.3.10 T'T'/T'dT'd - Temperature/Dew-point

example #1: 15/10
The air temperature is 15°C and the dew-point temperature is 10°C.

example #2: 01/M12
The air temperature is 1°C and the dew-point temperature is minus 12°C.

example #3: 00/M00
The air temperature is 0°C and the dew-point temperature is 0°C. (In this example the actual temperatures could be 0.4°C and minus 0.5°C respectively.)
 

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

This group reports the air temperature (T'T') and the dew-point temperature (T'dT'd), rounded to the nearest whole Celsius degree (e.g. +2.5°C would be rounded to +3°C). Negative values are preceded by the letter M, and values with a tenths digit equal to precisely 5 (e.g. 2.5, -0.5, -1.5, -12.5 etc.) are rounded to the warmer whole degree.

T'T'/T'dT'd - Temperature/Dew-point 


1.3.11 APHPHPHPH - Altimeter Setting 

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

This group reports the altimeter setting. A is the group indicator, and PHPHPHPH is the altimeter setting in hundredths of inches, using four digits. (Internationally, the group indicator is "Q", and the altimeter setting is reported to the nearest hectopascal.)

APHPHPHPH - Altimeter Setting

example: A3012
The altimeter setting is 30.12 inches of mercury.


1.3.12 REw'w' - Recent Weather 

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

This group reports recent weather of operational significance. The group indicator RE is followed, without a space, by the appropriate abbreviation(s) for weather observed during the period since the last (scheduled) routine report ("METAR"), but not observed at the time of observation. Recent weather is included in "METAR" and "SPECI" reports.

The following may be reported as recent weather phenomena:

  • Freezing precipitation;
  • Moderate or heavy drizzle, rain or snow;
  • Moderate or heavy ice pellets, hail or snow pellets;
  • Moderate or heavy blowing snow;
  • Sandstorm or duststorm;
  • Tornado, waterspout or funnel cloud;
  • Thunderstorm;
  • Volcanic ash. 
The same phenomenon is only reported as present weather (in w'w') and recent weather (in REw'w') if it was of greater intensity during the period since the last routine report. For example, with a moderate rainshower at 1800Z and a heavy rainshower at 1700Z (or later), the 1800Z METAR would report "SHRA" (in w'w') and "RERA" (in Rew'w').

REw'w' - Recent Weather

example #1: REFZRA
Freezing rain (other than ZR--) has occurred since the last routine report.

example #2: RERA
Moderate or heavy rain has occurred since the last routine report.

example #3: REBLSN
Moderate or heavy blowing snow has occurred since the last routine report.

example #4: 1440Z...SHRA...RERA
At 1440Z, a moderate rainshower is occurring....recent heavy rain has occurred since the 1400Z report.


1.3.13 WS RWYDRDR or WS ALL RWY - Windshear

METAR CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134

These groups report low level windshear (within 1600 feet AGL) along the takeoff or approach path. DRDR is the runway designator, to which the letters "L", "C", or "R" (left, centre, or right) may be appended. If the existence of windshear applies to all runways, WS ALL RWY is used.

WS RWYDRDR or WS ALL RWY - Windshear

example #1: WS RWY36R
Windshear was encountered on runway 36 right.

example #2: WS ALL RWY
Windshear was encountered on all runways.0


1.3.14 RMK - Remarks 

METAR CYYQ 171100Z 30024KT 1SM R33/3500FT ?SN BLSN BKN006 OVC022 M19/M23 A2978 RMK SF4NS4 VSBY 1/2?11/2 SLP134

Remarks will appear in reports from Canada and the U.S., prefaced by RMK. Remarks will include layer type and opacity (in oktas) of clouds and/or obscuring phenomena, general weather remarks, and sea level pressure (in hectopascals), as required.

RMK - Remarks

example # 1: RMK SC3CI0 SLP134
The clouds are Stratocumulus 3/8 opacity and Cirrus 0/8 opacity, and the sea level pressure is 1013.4 hPa.

example #2: RMK SF6AC1 ACSL OVR RDG NW SLP992
The clouds are Stratus Fractus 6/8 opacity and Altocumulus 1/8 opacity, with Altocumulus Standing Lenticular (mountain-wave clouds) over the ridge to the northwest, and the sea level pressure is 999.2 hPa.


1.4 METAR Examples 

The following are examples of METAR reports. The SA format is included for comparison. The METAR format for each example has been decoded.

EXAMPLE #1

METAR FORMAT

METAR CYOW 160800Z 21004KT 8SM -TSRA BKN020 OVC100 20/18 A2966 RMK SC5AC3 CB EMBDD
LTGCG SE SLP044=

SA FORMAT

YOW RS 0800 E20 BKN 100 OVC 8TRW- 044/20/18/2104/966/SC6AC4 CB EMBDD LTGCG SE 98XX=

METAR DECODED

STATION: OTTAWA
DATE/TIME: 16th at 0800 UTC
WIND: 210° TRUE AT 4 KNOTS
VISIBILITY: 8 STATUTE MILES
WEATHER: THUNDERSTORM LIGHT RAINSHOWER 
SKY CONDITION: BROKEN AT 2000 FEET OVERCAST AT 10000 FEET
TEMPERATURE: 20°C
DEWPOINT: 18°C 
ALTIMETER SETTING: 29.66 INCHES OF MERCURY
REMARKS: STRATOCUMULUS 5 OKTAS ALTOCUMULUS 3 OKTAS, CUMULONIMBUS EMBEDDED, LIGHTNING CLOUD TO GROUND SOUTHEAST, SEA LEVEL PRESSURE 1004.4 hPa
 

EXAMPLE #2

METAR FORMAT

METAR CYQX 141200Z CCB 32008KT 1/4SM FG VV002 09/08 A2963 RMK F8 SLP040=

SA FORMAT

YQX SA 1200 W2 X 1/4F 040/9/8/3208/963/F10 3008 94XX=

METAR DECODED

STATION: GANDER
DATE/TIME: 14th at 1200 UTC (second correction) 
WIND: 320° TRUE AT 8 KNOTS
VISIBILITY: 1/4 STATUTE MILES
WEATHER: FOG
SKY CONDITION: SKY OBSCURED VERTICAL VISIBILITY 200 FEET 
TEMPERATURE: 9°C
DEWPOINT: 8°C 
ALTIMETER SETTING: 29.63 INCHES OF MERCURY
REMARKS: FOG 8 OKTAS, SEA LEVEL PRESSURE 1004.0 hPa
EXAMPLE #3

METAR FORMAT

METAR CYYQ 241700Z 34011KT 2SM -DZ BR OVC004 05/05 A2994 RMK F4SF3 VSBY NE QUAD 1 SLP140=

SA FORMAT

YYQ SA 1700 -X M4 OVC 2L-F 140/5/5/3411/994/F5SF4 VSBY NE QUAD 1 299X=

METAR DECODED

STATION: CHURCHILL
DATE/TIME: 24th at 1700 UTC
WIND: 340° TRUE AT 11 KNOTS
VISIBILITY: 2 STATUTE MILES
WEATHER: LIGHT DRIZZLE AND FOG (MIST)
SKY CONDITION: OVERCAST AT 400 FEET
TEMPERATURE: 5°C
DEWPOINT: 5°C 
ALTIMETER SETTING: 29.94 INCHES OF MERCURY
REMARKS: FOG 4 OKTAS STRATUS FRACTUS 3 OKTAS, VISIBILITY NORTHEAST QUADRANT 1 MILE, SEA LEVEL PRESSURE 1014.0 hPa
 

EXAMPLE #4

METAR FORMAT

METAR CYYQ 301300Z 35011KT 1/8SM FG VV001 02/02 A2991 RMK F8 SLP131=

SA FORMAT

YYQ SA 1300 W1 X 1/8L--F 131/2/2/3511/991/F10 44XX=

METAR DECODED

STATION: CHURCHILL
DATE/TIME: 30th at 1300 UTC
WIND: 350° TRUE AT 11 KNOTS
VISIBILITY: 1/8 STATUTE MILES
WEATHER: FOG
SKY CONDITION: SKY OBSCURED VERTICAL VISIBILITY 100 FEET 
TEMPERATURE: 2°C
DEWPOINT: 2°C 
ALTIMETER SETTING: 29.91 INCHES OF MERCURY
REMARK: FOG 8 OKTAS, SEA LEVEL PRESSURE 1013.1 hPa
EXAMPLE #5

SPECI FORMAT

SPECI CYVR 061843Z 09008KT 4SM -SHRA BR BKN006 BKN015 OVC040 RMK CF6SC2SC1 TCU EMBDD=

SA FORMAT

YVR SP 1843 M6 BKN 15 BKN 40 OVC 4RW-F 0908 CF7SC2SC1 TCU EMBDD=

SPECI DECODED

STATION: VANCOUVER
DATE/TIME: 6th at 1843 UTC
WIND: 090° TRUE AT 8 KNOTS
VISIBILITY: 4 STATUTE MILES
WEATHER: LIGHT RAINSHOWER AND FOG (MIST) 
SKY CONDITION: BROKEN AT 600 FEET BROKEN AT 1500 FEET OVERCAST AT 4000 FEET
REMARKS: CUMULUS FRACTUS 6 OKTAS STRATOCUMULUS 2 OKTAS
STRATOCUMULUS 1 OKTA, TOWERING CUMULUS EMBEDDED

Note: In the above SPECI, as a result of rounding-off by the current input software, the layer opacities add up to 9 oktas. 
 

EXAMPLE #6

METAR FORMAT

METAR CYQB 201900Z 00000KT 3/4SM -SHRA BR BKN004 OVC020 19/18 A2962 RMK SF6SC2 SLP032=

SA FORMAT

YQB RS 1900 M4 BKN 20 OVC 3/4RW-F 032/19/18/0000/962/SF8SC2 10XX=

METAR DECODED

STATION: QUÉBEC
DATE/TIME: 20th at 1900 UTC
WIND: CALM
VISIBILITY: 3/4 STATUTE MILES
WEATHER: LIGHT RAINSHOWER AND FOG (MIST) 
SKY CONDITION: BROKEN AT 400 FEET OVERCAST AT 2000 FEET 
TEMPERATURE: 19°C
DEWPOINT: 18°C 
ALTIMETER SETTING: 29.62 INCHES OF MERCURY
REMARKS: STRATUS FRACTUS 6 OKTAS STRATOCUMULUS 2 OKTAS, 
SEA LEVEL PRESSURE 1003.2 hPa 


1.5 METAR Exercise 

Using the following Canadian METAR reports, answer the questions below:

CYVR 151100Z VRB03KT 1/4SM FG VV002 09/08 A2963 RMK F8 SLP998= 
CYYC 151100Z 09005KT 1 1/2SM ?SN BR OVC003 00/00 A2990 RMK F6SF2 SLP009=
CYEG 151100Z 00000KT 15SM FEW018 BKN040 OVC095 M00/M02 A2996 RMK CF2SC3AC3 SLP141=
CYZF 151100Z 28005KT 12SM ?SN FEW015 OVC025 M11/M13 A2988 RMK SF1SC7 SLP105=
CYYQ 151100Z 34015G30KT 1/2SM -SN BLSN VV005 M05/M07 A2975 RMK S8 SLP002=
CYUL 151100Z AUTO 04002KT 9SM BKN050 BKN090 00/M01 A3032 RMK SLP244= 
CYHZ 151100Z 00000KT 15SM BCFG FEW020 SCT100 SCT250 M00/M02 A3038 RMK CU1AS2CI0 SLP299=
CYYT 151100Z 00000KT 0SM FG VV000 07/07 A3019 RMK F8 SLP212=
CYAW 151100Z 03006KT 1 1/4SM ?RADZ BR OVC003 10/10 A2976 WS ALL RWY RMK SF7 CIG RGD SLP001=
CYQX 151100Z 30007KT 1/8SM FZFG VV001 M02/M03 A2998 RMK F8 SLP146= 
 

1. What is the altimeter setting at (CYYC) Calgary? 

2. What is the temperature at (CYYQ) Churchill? 

3. What is the dew-point temperature at (CYQX) Gander? 

4. What is the wind direction and speed at (CYYQ) Churchill? 

5. What is the wind direction and speed at (CYVR) Vancouver? 

6. What are the reported clouds at (CYUL) Montreal? 

7. What are the reported clouds at (CYHZ) Halifax? 

8. What is the sky condition reported at (CYVR) Vancouver? 

9. What is the visibility reported at (CYYC) Calgary? 

10. Which station(s) is reporting the greatest visibility? 

11. Which station is reporting the lowest cloud layer and what is the height?

i) station ii) height 

12. What is the present weather reported at (CYYQ) Churchill?

13. What is the present weather reported at (CYAW) Shearwater?

1.6 METAR Exercise Answers

CYVR 151100Z VRB03KT 1/4SM FG VV002 09/08 A2963 RMK F8 SLP998= 
CYYC 151100Z 09005KT 1 1/2SM ?SN BR OVC003 00/00 A2990 RMK F6SF2 SLP009=
CYEG 151100Z 00000KT 15SM FEW018 BKN040 OVC095 M00/M02 A2996 RMK CF2SC3AC3 SLP141=
CYZF 151100Z 28005KT 12SM ?SN FEW015 OVC025 M11/M13 A2988 RMK SF1SC7 SLP105=
CYYQ 151100Z 34015G30KT 1/2SM -SN BLSN VV005 M05/M07 A2975 RMK S8 SLP002=
CYUL 151100Z AUTO 04002KT 9SM BKN050 BKN090 00/M01 A3032 RMK SLP244= 
CYHZ 151100Z 00000KT 15SM BCFG FEW020 SCT100 SCT250 M00/M02 A3038 RMK CU1AS2CI0 SLP299=
CYYT 151100Z 00000KT 0SM FG VV000 07/07 A3019 RMK F8 SLP212=
CYAW 151100Z 03006KT 1 1/4SM ?RADZ BR OVC003 10/10 A2976 WS ALL RWY RMK SF7 CIG RGD SLP001 =
CYQX 151100Z 30007KT 1/8SM FZFG VV001 M02/M03 A2998 RMK F8 SLP146= 
 

1. What is the altimeter setting at (CYYC) Calgary? 29.90"

2. What is the temperature at (CYYQ) Churchill? minus 5 degrees Celsius

3. What is the dew-point temperature at (CYQX) Gander? minus 3 degrees Celsius

4. What is the wind direction and speed at (CYYQ) Churchill? 340° at 15 kts gusting to 30 kts

5. What is the wind direction and speed at (CYVR) Vancouver? wind variable at 3 kts

6. What are the reported clouds at (CYUL) Montreal? not available from autostation reports

7. What are the reported clouds at (CYHZ) Halifax? CU1AS2CI0

8. What is the sky condition reported at (CYVR) Vancouver? sky obscured vertical visibility
200 feet

9. What is the visibility reported at (CYYC) Calgary? 11/2 statute miles

10. Which station(s) is reporting the greatest visibility? CYEG and CYHZ

11. Which station is reporting the lowest cloud layer and what is the height?

i) station CYYC & CYAWii) height 300 feet

12. What is the present weather reported at (CYYQ) Churchill? light snow and blowing snow

13. What is the present weather reported at (CYAW) Shearwater? light rain and drizzle, and fog (mist)