How to Read a METAR Weather Report
Reading a METAR report and understanding weather is an important part of flying. When taking the FAA Part 107 exam for commercial operation of a sUAS, weather and reading METAR / TAF reports make up a large percentage of the test questions, so mastering weather is a must.
Like most things on the exam, weather looks like a giant mess when you first look at it - but when you break down the individual pieces of the reports things start to make sense. I'm going to start with a METAR report from the closest airport to me, Cleveland Hopkins Airport on the evening that I'm writing this article.
Cleveland Hopkins METAR Report
KCLE 220136Z 31006KT 10SM FEW020 BKN024 OVC049 22/21 A2984 RMK AO2 RAE04 P0000 T02220206Right now this might look like a jumble of letters and numbers, but let's walk through each part of the METAR, line by line.
METAR Station ID
KCLEK refers to the Continental United States. The three letters after it CLE, refers to the airport. In this case, Cleveland Hopkins Airport.
METAR Date & Time
220136ZThe first two digits 22 refers to the day of the month.
The next 4 digits 0136 refers to the time when the report was made. The Z refers to ZULU or UTC time.
METAR Modifier (If any)
Sometimes the METAR will have a COR or AUTO modifier after the Date & Time. COR means it is a corrected report and AUTO refers to an automated station.
METAR Wind Speed
31006KTThe first three digits 310 is the direction of the wind in degrees.
The second numbers 06 mean refer to the wind speed in knots.
KT means knots.
Other Wind Speed Terminology
VRB means that the wind direction can vary, and the gusts are usually light.
If there is a three digit number V three digit number (Example: 090V180), that means that the winds a variable from 90 degrees to 180 degrees. This term comes up when the wind varies over 60 degrees.
Wind direction, N=0, E=90, S=180, W=270
METAR Visibility
10SM
This refers to the visibility. The visibility in this example is 10 Statute Miles.
METAR Present Weather and Obscurations (If any)
In our METAR report, this isn't included, but let's use +SHRA.
The + means Heavy, SH means Showers and RA means Rain. Look at the legend below for the full list of possibilities.
Intensity
(-): Light
( ): Moderate [No prefix]
(+): Heavy
Descriptor
MI: Shallow
BC: Patches
DR: Low Drifting
BL: Blowing
SH: Showers
TS: Thunderstorm
FZ: Freezing
PR: Partial
Precipitation
DZ: Drizzle
RA: Rain
SN: Snow
SG: Snow Grains
IC: Ice Crystals
PL: Ice Pellets
GR: Hail
GS: Small Hail &/or Snow Pellets
UP: Unknown Precipitation
Obscuration
BR: Mist
FG: Fog
FU: Smoke
VA: Volcanic Ash
DU: Widespread Dust
SA: Sand
HZ: Haze
PY: Spray
Other
PO: Well-Developed Dust/Sand Whirls
SQ: Squalls
FC: Funnel Cloud Tornado Waterspout
SS: Sandstorm
DS: Duststorm
METAR Sky Conditions
FEW020 BKN024 OVC049
The next block means the sky conditions. The first three letters FEW are the codes for the amount of coverage in the sky.
SKC: Clear
CLR: Clear
FEW: Few
SCT: Scattered
BKN: Broken
OVC: Overcast
The next three digits 020 mean the amount of feet (in hundreds) in which the clouds are located.
In this case, there are Few at 2000 feet, Broken at 2400 feet and Overcast at 4900 feet.
METAR Temperature & Dew Point
22/21
The first two digits 22 represent the temperature in Celsius.
The second two digits 21 represent the dewpoint in Celsius.
To display negative numbers, there will be an M in front of the numbers (Example M04/02 = -04 degress C/ dewpoint: 2).
METAR Altimeter & Pressure
A2984
The A Represents "Altimeter". 2984 represents 29.84 inches of mercury for the pressure. This is used so pilots can ensure there altimeter is displaying the right altitude.
METAR Remarks (Decoding)
The final section is the remarks section, which is pretty difficult to understand because it has so many terms associated with them. Decoding a METAR Remarks section is something you'll want to have a legend of terms to understand, or invest a lot of time memorizing the table.
Our example means:
RMK AO2 RAE04 P0000 T02220206
RMK: Just means this is the Remarks section
AO2: Automated & has a precipitation sensor
RAE04: Rain Ended at 4 minutes past the hour
P0000: Hourly precipitation in hundredths of inches, 0 in this case.
T02220206: Hourly temperature and dew point in tenths degrees C, 22.2 20.6 in this case.
The remarks section I use to 'decode' the metar remarks is on dixwx.com, and use their abbreviations chart for more in-depth information.
Conclusion
Reading these METAR weather reports isn't easy! Especially the remarks section. But In my experience on the Part 107, no tricky questions have been asked about the remarks section of the METAR, only the main part of the report. That being said, I'd still read over the different versions of the METAR remarks and understand what they are saying just to make sure.
The main structure of the METAR is pretty straightforward after you know how to read the different messages and what to look for, again - other than that stinking remarks section! What is the toughest part of a METAR report for you to read?