An FAA short course on reading METARS can be found here
The following is an example of a METAR, a surface observation, from O' Hare
Airport. Just click on any of the cells to go to the help dealing with that particular
METAR is the scheduled observation taken at the end of each hour. SPECI is an observation
taken at an unscheduled time due to certain criteria that is met such as low visibility,
low clouds, frozen precipitation, or thunderstorms.
In this example, K refers to a North American Station and ORD is the three
letter id for O' Hare (from Old Orchard, it's original name). Other examples are KRFD
(Rockford Il), KAMA (Amarillo, TX) and KDEN (Denver, Co).
041656Z-Time and Date
The 04 represents the day of the month
The 1656 represents the time at which the observation went out
The Z represents that the time is in ZULU or UTC (Universal Time Code).
The 190 (the first three numbers) is the direction of the winds in degrees from
0 to 360 degrees (although you will never see 360 because after 350, it goes back to 0).
The 20 (next two numbers) is the speed of the winds in knots.
the G26 represents the wind gusts. In this case the gusts are 26 knots. Gust
will not always be on here...there is criteria which must be met in order to have a gust.
Simply, unless it's windy, you are not going to see gusts in the obsevation.
the KT simply means knots. It will always be at the end.
For winds speeds below 7 knots, you might see VRB005KT which means the wind direction
is variable. This is the idea of "light and variable" that you might see in a forecast.
For winds greater than 6 knots you might see 18015KT 150V210. The winds are from
180 degrees at 15 knots, but the direction is actually variable between 150 degrees and
210 degrees. In order to be variable above 6 knots, the winds must have at least a
60 degree variation.
The 6SM simply means 6 Statute Miles. Occasionally you might see visibility
up to 20 or 30 SM but for the most part it will go from < 1/4 (vis below 1/4 SM) up to
(-SHRA)-Present Weather and
(-) is the designator for light. Precipitation will either be light (-),
moderate ( ), or heavy (+) based on certain criteria that must be met. For more info
on that criteria, please see the FMH-1 link at the bottom of this page. For now, just
understand that it is simply the intensity of the snow, rain, hail, sleet, or freezing rain.
SH means showers and RA means rain. So the present weather is a light
The following is from the FMH-1 HANDBOOK. The entire handbook is linked
at the bottom of this page.
(see note 2)
VC In the
(see note 3)
DR Low Drifting
SG Snow Grains
IC Ice Crystals
PL Ice Pellets
GS Small Hail
VA Volcanic Ash
FC Funnel Cloud
(see note 3)
1. The weather groups shall be constructed by considering columns
1 to 5 in the table
above in sequence, i.e. intensity, followed by description, followed
by weather phenomena,
e.g. heavy rain shower(s) is coded as +SHRA
2. To denote moderate intensity no entry or symbol is used.
3. Tornados and waterspouts shall be coded as +FC.
BKN represents a broken sky. (The clouds cover 5/8 to 7/8 of the sky)
110 represents the clouds are at 11,000 feet (simply add 2 zeroes to get
The cloud cover will either be FEW (1/8 TO 2/8 cloud coverage), SCT (SCATTERED, 3/8
TO 4/8 cloud coverage, BKN (5/8-7/8 coverage), and OVC (OVERCAST, 8/8 Coverage).
You will often have more than 1 designator (i.e. SCT035 BKN090 OVC140)
An indefinate ceiling caused by fog, rain, snow, etc., will require a
designator as VV (Vertical Visibility). VV is the how high you can see
vertically into the indefinate ceiling.
Significant Clouds such as TCU (Towering Cumulus), CB, (Cumulonimbus, or a
shower/thunderstorm), or ACC (Altocumulus Castellanus) will be found on the en of a category (i.e. SCT035TCU)
12/08-Temperature and Dewpoint
12represents the temperature in Celcius
08represents the dewpoint in Celcius
If the temperature or dewpoint falls below 0 there will be an "M" before it (i.e. 03/M02).
"M" means minus.
A simply stands for Altimeter
3016 means 30.16 inches of mercury for the pressure.
RMK simply means REMARKS and marks the end of the standard
metar observation and the beginning of the remarks that are put in as
A02 means that the site is automated and HAS a precipitation sensor. If it
were AO1, there would be no precip sensor. This does not mean the site is
un-manned. If there is an AUTO after the ID in the metar ob, then
there is no observer.
There are many remarks, and the
FMH-1 (Federal Meteorological Handbook-1) at the bottom will give you
a full listing of them. Here are only a few
of the important and common remarks:
Volcanic Eruptions are in plain english
TORNADO, FUNNEL CLOUD, or WATERSPOUT
Peak Wind (PK_WND)
Wind Shift (WSHFT_time)
BINOVC (Breaks in Overcast)
BINOVC denotes a few, small clear patches in the overcast sky
Tower or Surface Visibility (TWR_VIS SFC_VIS)
CIG (Ceiling=Lowest BKN/OVC layer or height of VV)
i.e. BKN V SCT, VIS 2V3 [2 variable 3 miles], CIG 025V030 [2500 ft-3000ft])
CG: Cloud to ground
CC: Cloud to Cloud
CA: Cloud to Air
Beginning/Ending of Thunderstorms/Rain/Snow (TSB, SNE, RAB, etc)
Thunderstorm Location (TS_LOC_(MOV_DIR)
LOC=Location (N, NE, S, VC, OHD [Overhead], ALQDS [All Quadrants])
DIR=Direction (N, NE, S, etc)
Hailstone Size (GR_[size])
Virga (VIRGA_[ DIR])
Cumulonimbus or Cumulonimbus Mammatus (CB or CBMAM_LOC_(MOV_DIR).
Towering cumulus (TCU_[DIR])
Altocumulus castellanus (ACC_[DIR])
Standing lenticular or Rotor clouds (CLD_[DIR])
Pressure Rising or Falling Rapidly (PRESRR/PRESFR)
Sea-Level Pressure (SLP###)
Aircraft Mishap (ACFT_MSHP)
Snow Increasing Rapidly (SNINCR_amount this hour/total)
Hourly Precipitation Amount (P####).
3- and 6-Hour Precipitation Amount (6####)
24-Hour Precipitation Amount (7####).
Snow Depth on Ground (4/###)
Water Equivalent of Snow on Ground (9####)
Hourly Temperature and Dewpoint (Tsn###sn###)
sn=Type (0=above zero celcius, 1=below zero celcius)
###=celcius temperature to nearest tenth of a degree
6-Hourly Maximum Temperature (1sn###)
6-Hourly Minimum Temperature (2sn###)
24-Hour Maximum and Minimum Temperature (4sn######)
First three numbers=maximum temp to nearest tenth of a degree celcius
Last three numbers=mimimum temp to nearest tenth of a degree celcius
-Hourly Pressure Tendency (5a###)--see table 12-7 at the bottom for a (type)
RVR (Runway Visual Range, Rrrr/####ft)--will eventually be in the body!
r=runway, i.e. 31C, 21L, etc.
####ft=Distance of visual range (i.e. 6000ft, P6000ft [plus], m600ft [minus])
Table 12-7. Characteristics of Barometer Tendency
Taken from the FMH, linked at the bottom
higher than 3
|Increasing, then decreasing.
|Increasing, then steady, or increasing then
increasing more slowly.
|Increasing steadily or unsteadily.
|Decreasing or steady, then increasing; or
increasing then increasing more rapidly.
same as 3 hours
|Increasing, then decreasing.
|Decreasing then increasing.
lower than 3
|Decreasing, then increasing.
|Decreasing, then steady, or decreasing then
decreasing more slowly.
|Decreasing steadily or unsteadily.
|Steady or increasing, then decreasing; or
decreasing then decreasing more rapidly.