What is METAR and How Do Pilots Read the Weather?
Aviation Meteorology
METAR: The Raw Language of Air Safety
Understanding the report that decides if your flight leaves or stays grounded.
[Image of modern airplane cockpit dashboard with screens]
In aviation, there is no room for ambiguity. While a passenger might look out the window and say "it looks like rain," a pilot needs precise, standardized, and global data. This is where the METAR comes in.
What is a METAR?
The METAR (METeorological Aerodrome Report) is the gold standard in weather observation for aviation. It is not a forecast of the future; it is an instant snapshot of current conditions at a specific airport.
It is typically generated every 30 or 60 minutes (depending on the airport and changing conditions) and uses an alphanumeric code format established by ICAO, allowing a pilot from Japan to understand conditions in Chile without language barriers.
Key Fact: The METAR is the basis for critical decision-making, such as fuel calculation, required takeoff runway length, and landing feasibility.
Anatomy of a Report
At first glance, it looks like an incomprehensible line of code, but its structure is logical and sequential. Let's look at a real example:
EGLL 031400Z 23015KT 9999 FEW030 15/11 Q1018
📍 Where (EGLL) ICAO code for the airport (London Heathrow).
🕒 When (031400Z) Day 03 of the month at 14:00 Zulu time (UTC).
💨 Wind (23015KT) From 230 degrees at 15 knots speed.
👁️ Visibility (9999) More than 10 km (clear visibility).
☁️ Clouds (FEW030) Few clouds at 3,000 feet altitude.
🌡️ Temperature (15/11) 15°C ambient temp / 11°C dew point.
📉 Pressure (Q1018) QNH of 1018 hectopascals (key for altimeter setting).
Who uses this information?
Although it is public, the METAR is a professional tool used primarily by:
Pilots: To determine if conditions meet legal minimums for operation (VFR or IFR rules).
Air Traffic Controllers (ATC): To decide which runway is in use (based on wind) and manage aircraft separation.
Flight Dispatchers: To plan the route and necessary fuel load in case of diversion to an alternate airport.
The next time you fly, remember: that smooth takeoff started long before, with a precise reading of this simple line of text.