How to decode METARs and TAFs

STEP 1

Read a METAR from left to right

Start by separating the report at every space. The usual order is report type, four-letter station identifier, observation time, wind, visibility, present weather, sky condition, temperature and dew point, altimeter setting, and remarks. A group may be absent when it is not needed, so rely on the form of each group as well as its position.

Wind in a METAR is reported from true north. 31008KT means wind from 310 degrees true at 8 knots. A G introduces gusts, VRB means the direction is variable, and 00000KT means calm. Visibility in a U.S. METAR is in statute miles; P6SM means more than 6 statute miles.

FEW, SCT, BKN, and OVC describe increasing sky coverage. The three digits that follow give cloud-base height in hundreds of feet above ground level.
BKN and OVC layers can establish a ceiling; FEW and SCT layers do not by themselves.
18/09 means a temperature of 18°C and dew point of 9°C. An M before a value means below zero.
A3014 means an altimeter setting of 30.14 inches of mercury—not 3,014 feet and not a pressure altitude.

STEP 2

Treat a TAF as a timeline

The opening groups identify the airport, issue time, and valid period. After the initial forecast conditions, change groups tell you when a new set of conditions begins or when temporary or probabilistic conditions may occur. Keep those groups attached to the correct day; crossing midnight is one of the easiest ways to misread a forecast.

FM starts a new prevailing forecast at a specific UTC time. TEMPO describes temporary fluctuations during a stated interval. PROB30 identifies a 30-percent probability during its interval. Read every change group in sequence and carry forward any element that the new group does not replace.

2612/2718 means valid from 1200Z on the 26th until 1800Z on the 27th.
FM261800 means a new prevailing forecast begins at 1800Z on the 26th.
Do not read FM100000 as 1000Z; it means 0000Z on the 10th.
A TAF is a forecast for the airport vicinity, not a guarantee for every point along a route.

STEP 3

Use the report to ask operational questions

Decoding is only the first step. Ask whether visibility and ceilings meet the applicable rules and your personal minimums, whether wind favors a usable runway, whether a temperature/dew-point spread suggests worsening visibility, and whether forecast changes affect departure, arrival, or alternates.

Training reports are useful for pattern recognition, but an actual flight requires current official weather, NOTAMs, airport information, aircraft limitations, and sound aeronautical decision-making. Never substitute a practice decoder for a briefing.

WORKED EXAMPLE

Worked METAR example

METAR KATL 261452Z 31008KT 10SM FEW025 SCT120 18/09 A3014 RMK AO2

KATL: The four-letter station identifier.
261452Z: Observed on the 26th at 1452 UTC.
31008KT: Wind from 310° true at 8 knots.
10SM: 10 statute miles visibility.
FEW025 SCT120: Few clouds at 2,500 feet AGL and scattered clouds at 12,000 feet AGL.
18/09: Temperature 18°C; dew point 9°C.
A3014: Altimeter setting 30.14 inHg.
RMK AO2: Remarks begin; the automated station has a precipitation discriminator.

Takeaway: Read the groups in order, then step back and describe the whole weather picture in plain language.

COMMON QUESTIONS

Questions learners ask

What is the biggest difference between a METAR and a TAF?

A METAR is an observation of conditions at a particular time. A TAF is a forecast covering a future valid period and may contain several timed change groups.

Are METAR winds true or magnetic?

METAR and TAF wind directions are referenced to true north. Airport wind indications and tower-reported surface wind used operationally may be magnetic.

What does the Z mean in 261452Z?

Z means Coordinated Universal Time, commonly called Zulu time. The group says the observation was made on the 26th day of the month at 1452 UTC.