What Is a TAF? How to Read a Terminal Aerodrome Forecast Before You Fly

A TAF (Terminal Aerodrome Forecast) is a coded weather forecast issued for the area within about five statute miles of an airport, predicting wind, visibility, weather, and clouds for a 24- or 30-hour window. Think of it as the airport-specific forecast that tells you what conditions to expect at your departure or destination field, not just what’s happening right now.

If a METAR is the weather report — what the airport looks like right now — then the TAF is the weather forecast. It’s the FAA’s official prediction for that specific airport, written in the same shorthand code, and decoding it is one of the first real pilot skills you’ll pick up as a student. Let’s break it down so you can read one cold.

What does TAF stand for and what is it?

TAF stands for Terminal Aerodrome Forecast. It is a concise, coded statement of the expected weather conditions at an airport during a specified period, covering the area within approximately five statute miles of the center of the airport’s runway complex. It forecasts wind, visibility, significant weather, and sky condition. The TAF and METAR codes are both keyed in AIM 7-1-28, “Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR).”

The key word is terminal — this forecast is built around a single airport, not a region. That makes it the most precise weather forecast you’ll use for a takeoff or landing decision.

A TAF is produced by a forecaster at a National Weather Service Weather Forecast Office, drawing on observations, models, and the local METAR history. A human meteorologist has looked at that specific field and committed to a prediction — worth a lot when you’re deciding whether the ceiling will lift by the time you arrive.

What’s the difference between a TAF and a METAR?

A METAR is an observation — the actual weather at the airport right now. A TAF is a forecast — the expected weather at that same airport over the next 24 or 30 hours. They share almost the same code, so once you can read one, the other comes fast. The biggest difference is that a TAF adds change groups to describe how the weather will evolve over time.

The cleanest way to keep them straight: a METAR answers “what is it doing?” and a TAF answers “what will it do?” You’ll almost always read them together during preflight.

One thing that trips up new students: a TAF does not contain a temperature line the way a METAR does. TAFs forecast wind, visibility, weather phenomena, and sky condition — temperature appears only in limited cases, so don’t go hunting for the dewpoint group you’re used to seeing in a METAR.

How do you read a TAF line by line?

Read a TAF in the same order every time: station identifier, then the issuance date/time, then the valid period, then the first forecast line of wind, visibility, weather, and sky condition. After that, each change group (FM, BECMG, TEMPO, PROB) modifies the forecast for a later part of the valid window. The whole thing is in UTC, so convert to local first.

Let’s decode a realistic example:

KANC 181130Z 1812/1918 27012KT 6SM -SN BKN020 FM181700 28015G25KT 3SM SN OVC015

Breaking it apart:

• KANC — the station, Ted Stevens Anchorage International.
• 181130Z — issued on the 18th at 1130 Zulu.
• 1812/1918 — valid from the 18th at 1200Z through the 19th at 1800Z.
• 27012KT — wind from 270° at 12 knots.
• 6SM — visibility 6 statute miles.
• -SN — light snow.
• BKN020 — broken clouds at 2,000 feet AGL.
• FM181700 — from the 18th at 1700Z, the forecast changes to the conditions that follow.

Notice the valid-period format: 1812/1918 is day-and-hour, day-and-hour. That two-digit day in front of each time is what catches people off guard, so read it slowly. Cloud heights in a TAF are AGL, just like a METAR.

What do FM, BECMG, TEMPO, and PROB mean?

These are the four change groups that make a TAF a forecast instead of a snapshot. FM (from) marks a rapid, permanent change at a specific time. BECMG (becoming) marks a gradual change over a period. TEMPO (temporary) marks brief fluctuations expected to last less than an hour each. PROB (probability) states the percent chance of conditions, usually PROB30 or PROB40.

Here’s how each one behaves in the wild:

The one to respect most is TEMPO. When a TAF says TEMPO 1815/1818 2SM SHRA, it’s warning that for short bursts in that window, visibility could drop to 2 miles in rain showers — even though the prevailing forecast looks better. New pilots read the headline conditions and skip the TEMPO line. Don’t. That’s the line that ruins an otherwise easy arrival.

You won’t see PROB30 or PROB40 inside the first few hours of a TAF, and PROB is never combined with FM — formatting rules worth knowing for the Knowledge Test.

How often are TAFs issued and how long are they valid?

TAFs are normally issued four times per day, at 0000, 0600, 1200, and 1800 UTC, and are typically valid for 24 hours, though many busier airports carry a 30-hour TAF. Amended TAFs (marked TAF AMD) come out whenever conditions change enough to invalidate the original, and corrected versions are marked TAF COR.

Because the schedule runs on Zulu time, the freshest TAF depends on when you’re briefing. Pull weather at 1330 local in Alaska and you’re working off the 1200Z issuance — so check whether an amendment has come out since.

Always note the valid period before you trust a TAF. A forecast that expires before your estimated time of arrival isn’t doing you any good. That’s why a TAF is one input in your briefing, never the whole picture.

If you want a structured way to build this kind of preflight weather habit from day one, our free Total Student Pilot course walks you through reading real weather products step by step, and the full Private Pilot Ground School takes you all the way through the FAA Knowledge Test with weather decoding drills built in.

A real Alaska cross-country and a TAF that earned its keep

I learned to respect the TEMPO line on a Cessna 172 cross-country out of Anchorage years ago, with a student in the right seat. The prevailing TAF for our destination looked fine — broken ceilings, good visibility, a nice afternoon. But buried near the bottom was a TEMPO group calling for brief drops to 2 miles in snow showers right around our planned arrival.

My student wanted to launch and “see how it looks.” That’s a normal instinct. So we slowed down and read the whole TAF together, line by line, and talked through what that TEMPO line meant: not a sure thing, but a real chance the field could go from comfortable to marginal in minutes.

We built a plan around it instead of around the headline — picked an alternate, padded our fuel, set a hard decision point. Sure enough, on arrival the field cycled through exactly what the TAF warned about: clear one minute, snow shower the next. Because we’d read the forecast properly, none of it was a surprise.

That’s the whole lesson. A TAF rewards the pilot who reads all of it. The prevailing line gets you in the door; the change groups keep you out of trouble. Read both, every time.

Why don’t all airports have a TAF?

Not every airport gets a TAF. TAFs are issued for airports with enough traffic and operational significance to justify a dedicated forecast — generally towered fields and busier regional airports. Thousands of small, non-towered airports have no TAF of their own, so you forecast for them using the nearest TAF-issuing airport plus broader area products.

This matters for student cross-countries, because the little fields you’ll use as practice destinations frequently won’t have one. When that happens, find the closest airport that does, account for terrain and distance between the two, and lean on the area-wide forecast products to fill in.

Never assume a missing TAF means good weather. It just means no one wrote a forecast for that specific spot. Treat the absence of a TAF as a prompt to dig harder in your briefing, not as a green light.

PLT Study Guide

The FAA tags Knowledge Test questions with PLT (learning statement) codes. For Terminal Aerodrome Forecasts, two codes apply directly, and one supporting code is worth knowing. Note: the older hint code PLT284 actually refers to Winds and Temperatures Aloft, not TAFs — it does not apply here.

PLT072 — Interpret information on a Terminal Aerodrome Forecast (TAF). This is the hands-on decoding skill. You should be able to take a raw TAF string and pull out the station, issuance time, valid period, wind, visibility, weather, sky condition, and every change group. Practice reading the day/hour valid-period format (like 1812/1918) until it’s automatic.

PLT288 — Recall information on a Terminal Aerodrome Forecast (TAF). This is the conceptual side: knowing what a TAF covers (the ~5 statute mile area around the airport), how long it’s valid (24 or 30 hours), when it’s issued (0000, 0600, 1200, 1800 UTC), and what FM, BECMG, TEMPO, and PROB each mean.

PLT514 — Recall weather reporting systems (briefings, forecasts, reports, AWOS/ASOS). Supporting code. Understand where the TAF sits in the larger weather-briefing system and how it relates to METARs and automated observing systems that feed the forecast.

Frequently Asked Questions

You’ll read hundreds of TAFs over your flying career, and after the first dozen the code stops looking like code and starts looking like weather. The trick is reading every line — especially the change groups — and converting that Zulu time before you ever touch the throttle. Decode it slowly now and it becomes second nature later.

FROM CHRIS

Build the habit on the ground, and it’ll be there for you in the air.

Throttle On!

Chris Palmer

Founder & Chief CFI, Angle of Attack — Two-Time Master Aviation Educator and Gold Seal CFI