Aviation Weather: How to Read METARs and TAFs

The first time you see a METAR it looks like someone fell asleep on the keyboard. KORD 121651Z 28015KT 10SM FEW250 24/12 A2998. But that line is a dense, precise weather report, and once you can read it you will understand the sky the way pilots do. Better still for a spotter, the weather tells you which runway will be active and where the light will be, so learning this pays off the very next time you head out.

What METARs and TAFs Actually Are

A METAR is a current weather observation for an airport, usually updated about once an hour. A TAF is a terminal aerodrome forecast, a prediction of what the weather will do over the coming hours at that same airport. METAR is what is happening now; TAF is what is expected next. Pilots read both before every flight, and you can pull them for free from sources like the official aviation weather service or any number of flying apps.

Decoding a METAR, Field by Field

Let us walk through that example line one piece at a time, because every METAR follows the same order.

Station and Time

KORD is the airport, in this case Chicago O'Hare, written as its four letter ICAO code. 121651Z means the observation was taken on the 12th day of the month at 1651 Zulu, which is UTC. Aviation runs entirely on UTC to avoid time zone confusion, so you will need to convert it to local time in your head.

Wind

28015KT means the wind is coming from 280 degrees at 15 knots. Wind direction is always given as the heading it blows from, in degrees of magnetic compass, and this is the single most useful field for a spotter. A wind from 280 means the airport will favor its westerly runways, the 27s and 28s, so arrivals will be coming from the east. If you see a G in there, like 28015G25KT, that G marks gusts, here gusting to 25 knots.

Visibility and Weather

10SM means ten statute miles of visibility, which is clear and unrestricted. Lower numbers mean haze, fog, or precipitation is cutting the distance you can see. Any significant weather appears next as short codes: RA for rain, SN for snow, BR for mist, FG for fog, with a minus sign for light and a plus for heavy. A quiet day often has nothing here at all, which is exactly what our example shows.

Clouds and Ceilings

FEW250 describes the cloud layers, and this is where spotters and photographers should pay attention. The letters tell you how much sky is covered: FEW is a few clouds, SCT is scattered, BKN is broken, and OVC is overcast. The number is the height of that layer in hundreds of feet above the airport, so FEW250 means a few clouds at twenty five thousand feet, basically high and harmless. A line like BKN012 would mean a broken ceiling at just twelve hundred feet, low and gray, which changes both the mood of your photos and how the airport operates.

Temperature and Pressure

24/12 is the temperature and the dew point in Celsius, here 24 degrees with a dew point of 12. The closer those two numbers are, the more humid the air and the more likely fog or low cloud. Finally, A2998 is the altimeter setting, the local barometric pressure in inches of mercury, which pilots dial into their instruments. For spotting purposes you can mostly skip this last one, but now you know what it is.

Reading a TAF

A TAF looks similar but covers a span of time rather than a single moment. It starts with the airport and an issue time, then a validity period, followed by the forecast wind, visibility, weather, and clouds in the same format you just learned. The clever part is the change groups. FM followed by a time means from that time the conditions change to what follows. BECMG marks a gradual change over a period, and TEMPO marks temporary fluctuations that are expected to come and go. Read together, a TAF tells you not just the weather but when it is expected to shift.

Why Spotters Should Care

This is not just trivia. The wind in a METAR tells you which runways will be active, which tells you where to stand and which way the light will fall. The cloud and visibility fields tell you whether you are in for crisp blue sky shots or moody low approaches, and whether the airport might switch to instrument procedures that change the flow. Checking the TAF before a trip can save you from driving an hour only to find the weather turning, or tip you off that a front will swing the runways around mid afternoon.

A Simple Way to Practice

Pick your home airport and pull its METAR right now. Read the wind first and predict the active runway, then check the clouds and decide whether it is a blue sky or gray day. Do that a few times a week and it becomes automatic. Within a couple of weeks you will glance at a string that used to look like nonsense and instantly picture the sky over the field, which is a genuinely satisfying little superpower for anyone who loves airplanes.