METAR vs TAF: What’s the difference?

Both METAR and TAF pertain to the weather, specifically as they pertain to the flight of aircraft. Another thing that is common to them is the fact that they are highly abbreviated, making them quick to transmit but difficult to interpret for a layperson without using an interpretation tool. They also use very similar abbreviations and definitions.

However, why is there a need for distinction, and how are the two different?

METAR stands for Meteorological Aerodrome Report. The format of METAR reports is standardized by the International Civil Aviation Organization (ICAO) throughout the whole world. A METAR report contains information on the current weather conditions of the facility releasing the report. It is released according to a regular schedule unless sudden or exceptional weather changes occur.

TAF stands for Terminal Aerodrome Forecast. It is a report released by large airports that summarizes the weather forecast for the area covered by five statute miles from the location of the airport. A TAF report is valid for 24 to 30-hour time periods and is typically updated four times a day.

Thus, the distinction is quite clear – a METAR pertains to current weather conditions, while a TAF pertains forecasted weather for the next 24 to 30 hours.

Useful Tools

Many websites propose METAR and TAF Decoding. Here’s a reliable reference:
Metar-Taf

Here’s a good document issued by Australian Government explaining METAR/SPECI:
AUS GOV. METAR SPECI

As legitimate participants in national and international airspaces, this seems like a reasonable expectation that puts into consideration both your safety and the people, property, and other aircraft in your surroundings.

METARTAF

How to read a METAR weather report

As we’ve mentioned, both METAR and TAF are comprised of highly abbreviated codes for which you’ll likely need a decoding tool if you’re not used to them. To make the learning process easier, let’s start with a standard METAR transmission and break it down by parts:

METAR OLBA 180845Z 19004G10KT 10SM SHRA FEW018 SCT028 OVC040 18/02 Q1012 RMK RAE10 P0000 T01920101

TYPE OF REPORT

The first code to look for should be the identifier for the report. In our example, the report is clearly identified by the METAR term. In the absence of any identified, you can also assume that a weather report is transmitted in the METAR format.

While METAR reports are released regularly (usually hourly), unusual weather conditions can warrant the transmittal of unscheduled reports. These can be identified by the SPECI tag at the start of the report.

Think you can read METAR now?
Try Beirut International Airport’s actual METAR:

Single ICAO - METAR Example

Still need help?

Check the decoded actual METAR here

How to read a TAF weather forecast

If you already understand how to read a METAR weather report, then reading a TAF forecast should be much easier. After all, they share a common language. The only adjustment you’ll need to make with a TAF report is recognizing that it can have different parts pertaining to different times of the day.

OLBA 220520Z 2206/2312 VRB08KT 06SM PRSN SCT024 BKN030 OVC048

TEMPO 2209/2211 04SM SCT016 BKN024 OVC032

FM 221800 16010KT 06SM PRSN SCT030 BKN036 OVC054

STATION IDENTIFIER

Like a METAR, a TAF starts by identifying the station from which the report was transmitted. To keep our examples consistent, let’s use the same airport from the METAR section –Beirut International Airport (OLBA)

FORECAST CHANGE INDICATORS

In our example, the TAF is reported using several lines. This may not always be the case. On a beautiful day with no unusual weather patterns, a single-line TAF would be enough to provide weather forecast information for the next 24 or 30 hours. However, days when weather is expected to change quickly will demand multi-line TAF forecasts. Change indicators can start with either the ‘TEMPO’ or ‘FM’ terms, which we shall discuss separately.

TEMPO

TEMPO refers to temporary changes that typically last less than an hour. Meteorologists typically make these kinds of forecasts if the probability of them happening is more than 50%. The validity of a TEMPO forecast is given in a range, meaning that the temporary weather change may happen within this time period. In our case, the temporary change is expected to happen between 0900H and 1100H on the 22nd day (2209/2211).

A TEMPO forecast will only indicate weather indicators that are a departure from those indicated in the main TAF. Based on our example, a decrease in visibility is expected (04SM) as well as a lowering of the cloud ceiling. Beyond the time range given by the TEMPO, weather conditions expected to revert back to those indicated in the main TAF.

Think you can read TAF now?
Try Beirut International Airport’s actual TAF:

Single ICAO - METAR Example

Still need help?

Check the decoded TAF here