Automatic Terminal Information Service (ATIS)

The Automatic Terminal Information Service (ATIS) is a continuous, recorded broadcast of routine, non-control information at Canada’s busier airports: the current weather, the altimeter setting, the approaches in use, the active runway, and anything else pilots keep asking about. You listen to it before you call anyone, and you tell the controller which version you heard. It exists for one reason: so that a controller working a busy frequency never has to read the same weather report to forty aircraft in a row.

A Canadian ATIS, decoded line by line

Here is a typical broadcast from a towered airport in southern Ontario, taken apart element by element. The order is remarkably consistent from one airport to the next, which is exactly the point — after a few flights you stop hearing a wall of numbers and start hearing a checklist.

OSHAWA · INFORMATION BRAVOillustrative broadcast

This is Oshawa information Bravo Station + phonetic identifier — the letter advances with every new version, wrapping back to Alpha after Zulu. “Bravo” is the name of this snapshot in time.
Weather at one four zero zero Zulu Time of the observation, UTC — tells you how fresh the information is.
Wind two five zero at one two, gusting one eight Surface wind — degrees magnetic — spoken winds are magnetic so they line up with runway numbers. Written METARs are true. See the trap below.
Visibility one five miles Visibility in statute miles
Ceiling three thousand five hundred broken Sky condition, feet above ground — your VFR go/no-go number in a control zone.
Temperature two one, dew point one four Degrees Celsius — a narrowing spread hints at fog or carb icing conditions.
Altimeter two niner niner two Altimeter setting, inches of mercury — set it the moment you hear it.
IFR approach RNAV runway three zero, active runway three zero Approach in use + active runway — now you can plan your circuit entry or brief the approach before keying the mic.
Caution: bird activity in the vicinity of the field Operational remarks — pertinent NOTAMs, construction, closures, hazards.
Inform Oshawa ground on initial contact that you have information Bravo The part you must act on — say the letter on first contact, and the controller knows exactly what you know.

Invented for illustration — always fly with the current information, never a memorized format.

Why ATIS exists

Picture a tower frequency at a busy training airport on a clear Saturday morning. Every arriving and departing aircraft needs the same handful of facts: wind, altimeter, runway. Without ATIS, the controller reads that script dozens of times an hour — on the same frequency they need for the instructions that actually keep aeroplanes apart.

ATIS moves all of that routine traffic onto its own dedicated frequency, published in the Canada Flight Supplement and on charts. The controller records a new message (at many sites the voice is now computer-generated), pilots pull the information on their own time, and the control frequency is reserved for control. That is why the formal definition calls it non-control information: nothing on the ATIS is a clearance or an instruction. It tells you the picture; it never tells you what to do.

At most Canadian sites the ATIS is provided by the control tower; at some aerodromes a flight service station records it instead. Many broadcasts can also be reached by telephone — the number is in the CFS — which is a quietly excellent pre-flight habit: hear the field’s actual conditions from the flight planning room, before you have committed to anything.

How to actually use it

Listen before you talk to anyone. Departing, that means before your first call to ground or clearance delivery. Arriving, it means well outside the control zone, while you still have time and altitude to think about what you heard. The broadcast loops continuously; if you join mid-sentence, wait for the top.

Write down the letter, the wind, and the altimeter. Then say the letter on initial contact: “Oshawa ground, Cessna Golf Alpha Bravo Charlie, with information Bravo…” Those three words are doing real work. They tell the controller you already hold the current weather and runway, so none of it needs to be repeated. Miss them, and the controller has to confirm you have the information — which puts the congestion right back on the frequency that ATIS was invented to protect.

Notice when the letter changes. A new letter means something changed — and near the ground, the thing that changed is often the wind or the runway. If you copied Bravo twenty minutes out and the controller is now issuing Charlie, expect to hear “information Charlie current” and be ready for the update.

ATIS informs; it never instructs. Hearing “active runway 30” on the ATIS is not a clearance to fly to runway 30 — every clearance still comes from a controller, on a control frequency.

When is it updated?

An ATIS message is a snapshot, and it is refreshed whenever the snapshot goes stale: on receipt of each hourly weather observation, immediately when a special observation (SPECI) is issued for significant change, and whenever the operational details change — a runway switch being the classic case. Each new recording takes the next letter of the phonetic alphabet, and after Zulu the sequence wraps back to Alpha.

The letter is therefore a version number, and that is the elegant part of the whole system. Nobody has to compare weather values over the radio — two people just compare one letter. If your letter matches the current one, you and the controller are looking at the same picture of the airport.

The exam trap: magnetic wind vs. true wind

Here is the question that catches students every year. The METAR says wind 240°; the ATIS at the same airport, minutes later, says wind two five zero. Neither is wrong.

Written weather reports — METAR, TAF — give wind direction in degrees true, because they are produced for use with charts and navigation. Spoken wind — from the ATIS, the tower, or an FSS — is given in degrees magnetic, because it is meant to be compared directly against runway numbers, and runways in southern Canada are numbered to magnetic. A memory hook that survives exam pressure: if you read it, it’s true; if you hear it, it’s magnetic. (In the Northern Domestic Airspace, where compasses are unreliable, runways and winds work in degrees true instead — a refinement worth knowing for the written.)

ATIS vs. AWOS vs. METAR

Students meet all three in the first weeks of training, and they blur together because all three involve airport weather. They are different tools.

	ATIS	AWOS	METAR
What it is	Recorded broadcast of weather plus operational information	Automated weather sensors with a synthesized voice	Written, coded weather observation
Produced by	ATC or an FSS, at selected busier airports	A machine, typically at smaller aerodromes with no ATIS	An observing station (human or automated)
Tells you the runway and approach?	Yes — that is its distinguishing feature	No — weather only	No — weather only
Wind reference	Magnetic (spoken)	Magnetic (spoken)	True (written)
How you get it	Dedicated VHF frequency; phone at many sites	Dedicated VHF frequency; continuous	Flight planning briefing, apps, NAV CANADA website
Requires acknowledgement?	Yes — state the letter on initial contact	No	No

D-ATIS: the same idea, as text

At major Canadian airports the ATIS is also delivered as D-ATIS — Data Link ATIS — sent as a text message to suitably equipped aircraft over the ACARS datalink. Airline crews call it up on a cockpit display or printer instead of tuning a frequency and copying by hand: no mishearing “one five” as “one niner,” no waiting for the loop to come around. It is the same information with the same letter; only the delivery changes. You will not use it in a 172, but it appears in the TC AIM and it is the version of ATIS you will live with in an airline cockpit.

On the PSTAR, the radio exam, and the written

ATIS is one of the few glossary terms that follows you through every early exam. The PSTAR tests whether you know what the broadcast contains, that it is not a control service, and what you are expected to say on initial contact. The ROC-A radio examination expects the correct phraseology — the information letter belongs in your first call, not your third. And the PPL written likes the magnetic-versus-true wind distinction, usually dressed up as a METAR/ATIS comparison exactly like the one above.

The pattern across all three: ATIS questions are never really weather questions. They are questions about who is responsible for what on a busy frequency — and the answer is always that the pilot arrives already informed.

Radio work is learnable — and examinable. Our PSTAR preparation course drills every ATC and radio procedure on Transport Canada’s question bank, and our ROC‑A course and exam get the radio certificate itself done. Both online, both at your own pace.

Explore PSTAR Preparation

Related terms

Frequently asked questions

What does ATIS stand for, and what is it?

ATIS stands for Automatic Terminal Information Service: a continuous, recorded broadcast of routine, non-control information at busier airports. It carries the current weather observation, altimeter setting, approaches in use, active runway, and pertinent operational remarks, on a dedicated frequency published in the Canada Flight Supplement. Its purpose is to relieve frequency congestion — pilots collect the routine information themselves instead of having a controller repeat it to every aircraft.

How often is the ATIS updated?

Whenever the picture changes: on receipt of each hourly weather observation, immediately when a special observation (SPECI) is issued, and whenever operational details change, such as a runway switch. Every new recording takes the next phonetic letter — Alpha, Bravo, Charlie — wrapping back to Alpha after Zulu. A new letter is your cue that something is different.

Why do I have to say the information letter to ATC?

The letter is a version number. Stating it on initial contact — “with information Bravo” — confirms in three words that you hold the current weather, altimeter, and runway, so the controller doesn’t have to read any of it to you. If you omit it, the controller must confirm you have the information, which puts routine traffic back on the control frequency.

Is the ATIS wind magnetic or true?

Magnetic — like all spoken wind from a tower or FSS — so it can be compared directly against runway numbers. Written reports such as METARs and TAFs give wind in degrees true. The memory hook: if you read it, it’s true; if you hear it, it’s magnetic. In the Northern Domestic Airspace, where runways are numbered to true, spoken winds are given in degrees true as well.

What is the difference between ATIS and AWOS?

AWOS is an automated weather station with a synthesized voice: sensors reporting weather, and nothing else. ATIS is a recorded service produced by ATC or an FSS that includes the weather plus operational information — the approach in use, the active runway, and remarks — and it requires acknowledgement: you state the information letter on initial contact. Smaller aerodromes typically have an AWOS; ATIS is found at selected busier airports.

Is an ATIS broadcast a clearance?

No. ATIS is defined as non-control information. Hearing “active runway 30” tells you what to expect and lets you plan, but every taxi, takeoff, and landing clearance still comes from a controller on a control frequency. The ATIS informs; the controller instructs.

What is D-ATIS?

Data Link ATIS: the same ATIS message delivered as text over the ACARS datalink to suitably equipped aircraft, available at major Canadian airports. Airline crews retrieve it on a cockpit display instead of copying a voice broadcast, which eliminates listening time and transcription errors. The content and the information letter are identical to the voice version.