NAV CANADA and the Federal Aviation Administration stopped United States flights bound for Montréal-Pierre Elliott Trudeau International Airport from 3:15 p.m. to 4:45 p.m., Eastern, on Wednesday, August 12, 2026, citing transborder gate issues.
If you are on a Canada or contiguous United States departure into YUL this afternoon or evening, treat 4:45 p.m. as a pause, not an all-clear. The same operating day still sits under a ground delay program through 8:59 p.m., Eastern, with a published average delay of 65 minutes.
- Airport: Montréal-Trudeau (YUL) arrivals from Canada and the contiguous United States.
- Ground stop: 3:15 p.m. to 4:45 p.m., Eastern, for transborder gate issues.
- Delay program: 2:00 p.m. to 8:59 p.m., Eastern, averaging 65 minutes.
- Peak: New delay file lists 158 minutes maximum and 62 minutes average.
- Action: Recheck the airline app, protect connections, and stay at the origin gate.
What the official advisories actually say
The stop is not a rumor from a flight-tracking screenshot. The NAV CANADA CDM ground-stop advisory 015, posted at 1923Z, names Montréal as the control element and sets the stop from 1915Z to 2045Z, which is 3:15 p.m. to 4:45 p.m., Eastern.
The same notice keeps a cumulative program period of 1800Z to 0059Z, or 2:00 p.m. through 8:59 p.m., Eastern. The stop lists United States air-route centers that feed YUL, including New York, Washington, Boston, Atlanta, Chicago, Dallas, and Houston. Fixed-base operator parking is excluded, so general-aviation ramps are not the reason the airline gates froze.
A ground stop is the blunt tool. Controllers hold departures at the origin so they do not launch into an arrival bank that YUL cannot park. A ground delay program is the meter underneath it. Aircraft may still leave, but they leave later, on assigned times, so the arrival stream matches the airport’s accepted rate.
The earlier NAV CANADA CDM ground delay program advisory 008 had already set that meter for all Canadian and contiguous United States departures at 26 arrivals an hour, with a 115-minute maximum and a 65-minute average. The impacting condition was reduced system capacity, reduced airport capacity, and forecast weather.
After the stop posted, the delay file jumped from 237 flights, 89 minutes maximum, and 24 minutes average to 621 flights, 158 minutes maximum, and 62 minutes average. Probability of extension was medium. That is the official record as of 1922Z, not a traveler anecdote.
What this does to a United States departure
Imagine you are sitting at a gate in Boston, New York, Washington, Atlanta, Chicago, or Dallas with a midafternoon Montréal arrival. The stop means your aircraft should not push for YUL while the window is active, even if the boarding door is closed.
The airline app may still show the original departure time for several minutes. That lag is normal. The operating constraint is the arrival slot at YUL, not the painted time on your boarding pass.
The transborder piece matters because Montréal’s United States arrivals do not use the same gate and customs path as a domestic Canadian hop. When those gates are blocked, an inbound from LaGuardia or Atlanta cannot simply slide into any open door. That is why a passenger already in the air from Europe can still land while a regional jet in Cleveland stays parked: the stop targets the short-haul feeders that can still be held.
Independent tracking matches the official delay story. FlightAware’s Montréal-Trudeau status page showed departure delays averaging 33 minutes and decreasing during the same afternoon. The live 1900Z weather report listed rain showers, a 16-knot wind gusting to 23, and a forecast that still carried thunderstorms later in the program window. Weather is why the delay program existed before the gate stop arrived. The stop then stacked a parking problem on top of a capacity problem.
Why 4:45 p.m. is not the end of the day
A ground stop has a published end. A ground delay program can keep assigning later wheels-off times for hours after that end. If 4:45 p.m. arrives and the stop is not extended, United States departures can start moving again, but they move into a 26-arrival-hour meter that already advertised 65-minute averages.
The new delay file’s 158-minute maximum is worse than the earlier 115-minute GDP figure. That number is an assigned delay, not a promise that every flight will be that late. It is still the right planning number for a tight connection. If your inbound is supposed to land at 5:30 p.m. and your outbound leaves at 6:20 p.m., the math no longer works.
Same-day rebooking is the useful move while later Montréal seats, or a Toronto or Ottawa workaround, still exist. Overnight hotel and meal policies vary by carrier and by whether the delay is coded as weather, airport, or carrier-controlled. Do not assume a hotel voucher because the FAA page used the words ground stop.
Air Canada operates the largest share of the YUL transborder map. Deep Arrival’s Air Canada guide is the place to check cabin, connection, and Aeroplan mechanics after you know whether today’s flight still exists. This Wednesday file is also a new operating day, not a rewrite of Sunday’s Montréal arrival metering on August 9.
Three checks if you are already in motion
First, open the airline app and the live flight status page before you leave security or the lounge. If the departure has a new estimated time, screenshot it. That image is the record you will need if a missed connection later becomes a refund argument.
Second, do not abandon a held aircraft to chase a self-transfer. If you built a cheap Montréal connection onto a separate ticket, the stop can kill the first flight while the second carrier still marks you a no-show.
Third, if you are already on the ground in Montréal and heading onward to the United States, build extra time for the transborder checkpoint and for a departing aircraft that may now be waiting on the same constrained gate pool. A 45-minute connection that looked legal this morning is the first itinerary to break.
If the airline cannot move you until Thursday morning, Deep Arrival’s Montréal things-to-do guide is useful only after you have a confirmed hotel and a new flight. Do not leave the terminal for the city until those two pieces exist.
The FAA National Airspace System status board remains the fastest official check after this article is published. If advisory 015 disappears and advisory 008 remains, the stop ended and the meter is still running. If a new YUL stop posts, the 4:45 p.m. clock was superseded.
What is confirmed and what is still open
Confirmed: a same-day YUL ground stop for transborder gate issues from 3:15 p.m. to 4:45 p.m., Eastern; a same-day GDP through 8:59 p.m. for Canadian and contiguous United States departures; a 26-arrival hourly rate; published averages of 65 minutes on the GDP and 62 minutes after the stop; and a medium chance the stop would be extended.
Not confirmed in the public advisories: how many transborder gates were blocked, which airlines lost the most turns, and whether later thunderstorms will force a second restriction after dinner. FlightAware’s 36 cancellations in the trailing 24 hours mix earlier banks with this afternoon and should not be treated as the stop’s cancellation count.
Keep the three actions separate. Recheck the live status. Protect or rebook the connection. Stay with the held aircraft until the airline releases you or rebooks you. The dated window is 3:15 p.m. through 8:59 p.m., Eastern, on August 12, unless a later advisory replaces it.
| If you… | What to do |
|---|---|
| Are booked to YUL from a United States airport this afternoon | Stay at the origin gate, refresh airline status, and wait for a new release time. |
| Have a Montréal connection under 90 minutes | Rebook now. The published average delay already exceeds most legal connects. |
| Are already airborne toward YUL | Plan extra time for transborder gates and a late outbound. Do not count on a tight bank. |
| Need to be in Montréal tonight for a nonrefundable event | Ask the airline for the next guaranteed arrival, then compare a Toronto or Ottawa hop. |
| See the stop expire at 4:45 p.m. | Recheck the GDP. The 8:59 p.m. meter can still assign hour-plus delays. |
- Now: Recheck the airline app and the FAA YUL advisories before leaving the origin gate.
- Connect: Rebook any Montréal connection inside 90 minutes while later seats remain.
- After 4:45 p.m.: Treat the GDP through 8:59 p.m. as the live constraint, not the expired stop.
- Overnight: Confirm a hotel and a new flight before leaving the terminal for the city.
If your United States to Montréal flight is still showing a same-day arrival, keep watching the airline and the FAA board through 8:59 p.m. If it is not, take the rebooking that gets you there tomorrow with a legal connection rather than chasing a vanished 4:45 p.m. restart.
Is Montréal airport closed on August 12?
No. The official product is a transborder ground stop into YUL plus a same-day ground delay program, not a full airport closure.
Does the 4:45 p.m. ground stop end all delays?
No. The ground delay program still runs through 8:59 p.m., Eastern, with a published 65-minute average unless a later advisory changes it.
Which flights are in the stop?
The stop lists United States air-route centers feeding YUL and excludes fixed-base operator parking. Canadian and contiguous United States departures are in the broader delay program.
Should I go to the airport anyway?
Yes if your airline still shows the flight as operating and has not issued a new departure. Recheck status before you leave home, then stay with the gate until you are released or rebooked.
