Denver (DEN) to Washington (IAD): On-Time Performance
Data through July 2026
Denver (DEN) to Washington (IAD) effectively runs on two schedules. In January 2026, 89% of arrivals were on time; in July 2025 that fell to 63% — a 26-point seasonal swing. Across the full period the route averages 80% on-time against a national 78%. Morning departures also hold up better than evening ones (85% vs 71%), which matters most in the rough months.
- On-time
- 80%
- arrived <15 min late
- Avg delay
- 14 min
- completed flights
- Cancelled
- 0.6%
- Flights/day
- 9.5
- last 12 months
- Duration
- 3h 22m
- scheduled
- Distance
- 1,452 mi
Best airline from DEN to IAD
2 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 83% | 13 min | 0.6% | 5,598 |
| Southwest Airlines | 69% | 18 min | 0.5% | 1,651 |
Monthly on-time trend
Best time to fly from DEN to IAD
Aim for departures around 6 a.m. (93% on-time); avoid 7 p.m. departures (51%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 79% | 14 min |
| Tuesdaybest | 82% | 12 min |
| Wednesday | 80% | 12 min |
| Thursday | 79% | 13 min |
| Friday | 81% | 17 min |
| Saturday | 78% | 14 min |
| Sunday | 77% | 14 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft47%
- Airline operations31%
- National airspace system20%
- Weather1%
Frequently asked questions
- How often are flights from DEN to IAD delayed?
- 21% of DEN–IAD flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 14 minutes.
- Which airline is most reliable from DEN to IAD?
- United Airlines has the best on-time record on this route at 83%, based on 5,598 flights. 2 airlines flew DEN–IAD frequently enough to compare in this period.
- What is the best time of day to fly from DEN to IAD?
- Departures around 6 a.m. have the best record (93% on-time), while departures around 7 p.m. have the worst (51%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from DEN to IAD?
- The scheduled DEN–IAD flight time averages 3h 22m over 1,452 miles. Actual arrival times vary — flights on this route land 15+ minutes late 21% of the time.
- How often are DEN to IAD flights cancelled?
- 0.6% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from DEN to IAD?
- July 2025 was the roughest month in this dataset, with only 63% of arrivals on time. The best was January 2026 at 89%. If your dates are flexible, that 26-point gap is worth planning around.
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Based on 7,249 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.