One thing I always used to wonder in my early years of aviation was, what does all the METAR data and numbers actually mean? Well if you were also wondering this just as I was then the answers are here below! Also remember I am not an instructor or qualifed as such so always check with your training provider first. So make sure you are sitting comfortably because there is a lot of information here!
Ok so, METAR is a format for reporting weather information. It stands for Meterorological Terminal Aviation Routine Weather Report. Various other administrations name it slightly different but this is what I know it by. METAR typically come from airports or weather observation stations and are generated every half-hour to an hour. Sometimes special reports are issued if conditions change significantly. Some are encoded by automated airport weather stations at airports, military bases and other sites.
What does it contain?
A typical METAR string contains the current data for temperature, dew point, wind direction and speed, precipitaion, cloud cover and heights, visibility and barometric pressure. Got all that? Thats alot of information right? Theres more sometimes it may contain preciptation amounts, lightning and other information that might be useful to the pilot. So how do we read it? Well heres a recent METAR data string that we can use to decode the information that I will break down for you in bullet points.
How do we read it?
EGCC 241450Z AUTO VRB02KT 5000 HZ BKN021 OVC026 09/08 Q1002
- EGCC – this first 4 letter code is the ICAO airport code and this particular code is for Manchester Airport, UK
- 241450Z – This indicates the times of the observation starting with the day of the month (24) followed by the time of the day (1450Z) Z for zulu time which in this case is 2.50pm GMT
- AUTO – Automated encoder
- VRB02KT – So this box can change and it is the wind direction and speed, in this case we have variable wind direction and speeds of 02 knots.
- 5000 – This is the amount of prevailing visibilty at the weather station in this case 5,000 meters
- HZ – Here we have the current weather conditions in this case it is Haze
- BKN021 – The next sections describe the cloud cover and conditions so here we have Broken sky at 2,100 feet above the aerodrome.
- OVC026 – Then we have Overcast sky at 2,600 feet above the aerodrome, these figures do change frequently depending on conditions. From a pilots perspective on take off you would hit broken clouds at 2,100 and then overcast at 2,600. Weather above that would be expected to be clear
- 09/08 – Towards the end of the transmission we have temperature and dewpoint, first is temperature 09 degrees C and dewpoint 08 degrees C
- Q1002 – Finally we have the QNH reading which is the Sea-level pressure and this reads 1002mb
Got all of that?
So as you can see now the data is fairly easily readable now you know what you are looking at! These figures change all of the time with different abbreviations. I will look at making a page that lists them all should people want that so that you can reference it. I have added a sidebar with updatable METAR readings from Manchester so we can all practice!
Hope you all enjoyed this and looking forward to the next one! Take a look at the APU article too! Thank you for reading if you got to this point!