Washington Dulles International (IAD) Delays and On-Time Departures
Washington, DC · ranked 79th of 333 airports for on-time departures
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, Washington (IAD) had 58,031 scheduled departures and 83.8% of them left on time (US average 77.4%).
That ranks 79th of 333 US airports tracked on this site, with 1.4% of departures cancelled.
Among airlines at Washington (IAD), United Airlines left on time most often (85.3%).
Over 24 months, Tuesday was the most reliable day (86% on time) and July the worst month (73%).
Best time of day to fly out of Washington (IAD)
On-time departure % by scheduled departure hour (local time), last 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | 90.9% | 1.3% | 556 |
| 6am–7am | 91.5% | 1.2% | 6,739 |
| 7am–8am | 87.2% | 1.2% | 3,417 |
| 8am–9am | 91.1% | 0.9% | 21,612 |
| 9am–10am | 89.5% | 1.2% | 5,060 |
| 10am–11am | 86.8% | 1.4% | 1,752 |
| 11am–12pm | 84.6% | 0.9% | 1,129 |
| 12pm–1pm | 86.6% | 1.1% | 15,835 |
| 1pm–2pm | 85.8% | 1.0% | 4,552 |
| 2pm–3pm | 79.5% | 1.0% | 1,628 |
| 3pm–4pm | 80.2% | 0.6% | 3,788 |
| 4pm–5pm | 76.8% | 1.0% | 2,188 |
| 5pm–6pm | 76.0% | 1.6% | 24,722 |
| 6pm–7pm | 70.5% | 1.3% | 4,108 |
| 7pm–8pm | 72.7% | 1.4% | 2,775 |
| 8pm–9pm | 68.2% | 2.5% | 1,428 |
| 9pm–10pm | 60.5% | 1.7% | 232 |
| 10pm–11pm | 79.5% | 2.0% | 12,621 |
| 11pm–12am | Limited data | 4 | |
Airlines at IAD ranked by on-time departures
Last 12 months. Airlines with fewer than 30 departures are marked “limited data”.
| Airline | On-time departures | On-time arrivals | Cancelled | Departures |
|---|---|---|---|---|
| United Airlines | 85.3% | 82.5% | 0.9% | 36,755 |
| Republic Airways | 84.7% | 82.2% | 2.7% | 8,800 |
| PSA Airlines | 82.2% | 84.7% | 3.1% | 978 |
| Delta Air Lines | 81.8% | 80.8% | 2.5% | 3,098 |
| Alaska Airlines | 80.2% | 74.8% | 1.0% | 1,253 |
| SkyWest Airlines | 79.6% | 79.7% | 2.1% | 2,475 |
| American Airlines | 77.3% | 77.6% | 2.5% | 1,465 |
| Allegiant Air | 77.0% | 73.8% | 0.7% | 570 |
| Frontier Airlines | 73.5% | 69.5% | 2.3% | 1,652 |
| Southwest Airlines | 70.2% | 75.7% | 0.8% | 985 |
80%+ good 70–79.9% fair <70% poor
Best day to fly out of IAD
On-time departures by day, 24 months.
Best month to fly out of IAD
On-time departures by month, 24 months.
Holiday travel at Washington (IAD)
On-time departures during holiday periods compared with all other days, last 24 months.
| Period | On-time departures | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 84.3% | -1.0 pts | 0.4% | 2,154 |
| Christmas & New Year (Dec 20 - Jan 3) | 78.1% | -7.2 pts | 0.6% | 4,525 |
| Summer peak (Jun 15 - Aug 15) | 74.7% | -10.6 pts | 2.3% | 20,889 |
| All other days | 85.3% | — | 1.1% | 86,578 |
Monthly on-time departure trend at IAD
On-time departure % each month, with the 12-month US average for reference.
Routes from Washington (IAD)
Every route from IAD with its own page, by number of flights (last 12 months, on-time arrivals).