On August 12, 2026, the FAA held delay programs affecting 19 airports across the United States, with a total of 32 separate programs logged. The airport experiencing the most severe disruption was Toronto Pearson Airport (YYZ), subjected to multiple delay programs due to thunderstorms, with peak maximum delays reaching 262 minutes.
Delay Programs Active at 19 U.S. Airports, Including Ground Stops and Ground Delays
Nine ground stop programs were in place, which hold departures at their origins bound for specified airports. Eleven ground delay programs, which meter arrivals by assigning later departure times, were also active. Additionally, twelve general arrival and departure delay advisories were reported.
The worst-affected airport, YYZ, was under a ground stop program due to thunderstorms from 19:00 to 22:20 UTC, spanning 3 hours and 20 minutes. It also had a concurrent ground delay program from 16:40 to 22:20 UTC lasting 5 hours and 40 minutes, with peak maximum delays hitting 212 minutes.
Chicago O’Hare International Airport (ORD) experienced the longest
duration of delay programs. It was under a ground delay program affected by thunderstorms for 6 hours and 40 minutes, from 14:20 to 21:00 UTC. ORD also had a ground stop from 15:20 to 16:00 UTC (40 minutes) and general delay information for nearly 5 hours with peak average delays reaching 121 minutes.
Other airports with significant ground stop programs due to thunderstorms included Chicago Midway International (MDW) for 40 minutes and Harry Reid International (LAS) for 40 minutes. Denver International (DEN) and Orlando International (MCO) had short ground stops of 20 minutes related to thunderstorms.
Additional ground delay programs
with longer durations include San Diego International (SAN) affected by airport volume for 7 hours and 40 minutes, YUL under a 7-hour delay program with unspecified “other” reasons, and San Francisco International (SFO) facing a 4 hour and 20 minute program due to low ceilings.
| Airport | FAA programme | Cause | Peak average delay | In force (UTC) |
|---|---|---|---|---|
| YYZ | Ground Stop Programs | thunderstorms | – | 19:00 to 22:20 (3 hours 20 minutes) |
| Chicago Midway International (MDW) | Ground Stop Programs | thunderstorms | – | 15:00 to 15:40 (40 minutes) |
| Chicago O’Hare International (ORD) | Ground Stop Programs | thunderstorms | – | 15:20 to 16:00 (40 minutes) |
| Harry Reid International (LAS) | Ground Stop Programs | thunderstorms | – | 21:20 to 22:00 (40 minutes) |
| CAE | Ground Stop Programs | other | – | 01:40 to 02:00 (20 minutes) |
| LaGuardia (LGA) | Ground Stop Programs | airspace volume | – | 19:00 to 19:00 (20 minutes) |
| YUL | Ground Stop Programs | other | – | 19:40 to 20:00 (20 minutes) |
| Denver International (DEN) | Ground Stop Programs | thunderstorms | – | 20:00 to 20:20 (20 minutes) |
| Orlando International (MCO) | Ground Stop Programs | thunderstorms | – | 20:20 to 20:40 (20 minutes) |
| Newark Liberty International (EWR) | Ground Delay Programs | thunderstorms | 176 min | 00:00 to 00:00 (20 minutes) |
| LaGuardia (LGA) | Ground Delay Programs | thunderstorms | 120 min | 00:00 to 00:00 (20 minutes) |
| Chicago O’Hare International (ORD) | Ground Delay Programs | thunderstorms | 104 min | 14:20 to 21:00 (6 hours 40 minutes) |
| Denver International (DEN) | Ground Delay Programs | thunderstorms | 82 min | 20:40 to 22:20 (1 hour 40 minutes) |
| YUL | Ground Delay Programs | other | 78 min | 15:20 to 22:20 (7 hours) |
Thunderstorms Dominated Causes, Followed by Other and Airport Volume Issues
Of the FAA’s stated reasons, thunderstorms were the leading cause, involved in 67 incidents, driving six of the nine ground stop programs and many ground delays. The FAA also categorized delays under “WX:Thunderstorms,” accounting for 36 incidents primarily in general arrival and departure delay advisories.
Other causes included unspecified “other” reasons appearing 40 times, airport
volume causing 24 delay programs, and low ceilings responsible for 21. These figures correspond to FAA’s official delay cause classifications.
Delay Levels and Trends Compared to Previous Days
On August 12, peak average delay minutes were 176 with peak maximum delays reaching up to 262 minutes, measured primarily at Newark Liberty International and Toronto Pearson Airports.
Compared to the previous day, the number of airports affected increased by one from 18 to 19. The total number of programs also rose slightly from 29 to 32. Both figures remain below the 7-day average of 22.3 airports affected and suggest that August 12 was not the worst day in this
tracking period.
All delay programs and causes data are based on FAA data tracked by travelandtournews.com.
Methodology. travelandtournews.com samples the FAA’s National Airspace System status feed every 20 minutes throughout the US operating day and aggregates the result. This report is built from 68 samples taken between 00:00 and 22:20 UTC on 2026-08-12. Durations are the observed window between the first and last sample in which a programme was in force, so a programme’s true length may be slightly longer than shown. Ground stops, ground delay programmes, airport closures and general delays are all published by the FAA in real
time; the daily aggregation is ours.
