The Federal Aviation Administration (FAA) imposed a ground stop at Denver International Airport (DEN) on August 15, 2026, at 3:25 p.m. due to severe thunderstorms affecting final approach paths. The restriction delayed or cancelled over 700 flights, halting arrivals to prevent planes from circling overhead during heavy rain, hail, and flash flooding risks over the Colorado Front Range.
Flight tracking data showed that United Airlines had 216 delayed flights and four cancellations initially; later counts rose to 34 cancellations and 265 delays. Southwest Airlines had 249 delays and three cancellations initially, growing to 14 cancellations and 211 delays. SkyWest recorded
157 delays and 10 cancellations at first, reaching 38 cancellations and 121 delays later. Frontier Airlines cancelled eight flights initially and later five cancellations and 49 delays were reported.
The FAA lifted the ground stop at 4 p.m. but predicted significant delays would persist through the evening, with a ground delay program expected until 9:59 p.m. The National Weather Service issued a severe thunderstorm watch for the Front Range, including Denver, until 9 p.m., warning of damaging winds, large hail, and rainfall rates approaching 1 to 2 inches in 30 minutes.
The ground stop was caused by severe thunderstorms as
part of the North American Monsoon, which brings subtropical moisture into Colorado from mid-July through August, generating fast-forming afternoon storms over the High Plains and Front Range foothills. Convective storm cells produce strong outflow winds across DEN’s runways, disrupting arrivals and departures. DEN’s high elevation and position expose it to these weather events, marking it as one of the FAA’s “Core 30” airports vulnerable to weather delays.
Departures from the contiguous United States to Denver experienced an average delay of 114 minutes, with weather-related delays averaging 1 hour and 44 minutes. Flights continued to experience delays and cancellations throughout the
day as storms persisted. The ongoing weather created flash flooding risks and damaging winds in the Denver metro area and surrounding Front Range.
Denver International Airport served over 82.4 million passengers in 2025, ranking as the fourth-busiest U.S. airport. United Airlines operates its second-largest hub at DEN and carried over 41.4 million passengers through DEN in 2025, setting company records. Airlines United, Southwest, and Frontier control around 88% of seat capacity at the airport, concentrating air traffic and amplifying the effect of weather disruptions. The airport’s economic impact is estimated at $47.2 billion annually.
