Route Reliability
Washington → Denver
IAD–DEN · 1,452 miles · Washington Dulles International Airport to Denver International Airport
- 82%
- Arrive within 15 minutes
- 4 min
- Average arrival delay
- 0.7%
- Cancelled
- 3,624
- Flights in the data
Data through May 2026.
Who flies it best
Ranked by on-time arrivals. Historical results, not predictions.
- 1.United Airlines84%2,787 flights
- 2.Southwest Airlines76%837 flights
What the data says
Morning flights do better here.
IAD–DEN flights departing between 3–6 AM arrived on time 92% of the time, versus 62% between 6–9 PM.
Thursday is the weak spot.
IAD–DEN flights arrived on time 85% of the time on Saturdays. On Thursdays: 77%.
United Airlines runs this route best.
United Airlines arrived on time 84% of the time on this route; Southwest Airlines managed 76%.
Best historical flights
Ranked by on-time arrivals, minimum 100 flights. Past performance, not a promise.
Top flights by on-time rate
More flights on this route
The breakdown
- Mon84%(527 flights)
- Tue83%(503 flights)
- Wed82%(510 flights)
- Thu77%(522 flights)
- Fri81%(522 flights)
- Sat85%(482 flights)
- Sun82%(507 flights)
- 3–6 AM92%(180 flights)
- 6–9 AM89%(614 flights)
- 9 AM–12 PM92%(389 flights)
- 12–3 PM86%(819 flights)
- 3–6 PM74%(876 flights)
- 6–9 PM62%(356 flights)
- 9 PM–12 AM84%(339 flights)
Jun 74% → May 86% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 74% | 321 |
| July 2025 | 70% | 348 |
| August 2025 | 76% | 328 |
| September 2025 | 86% | 293 |
| October 2025 | 85% | 283 |
| November 2025 | 92% | 275 |
| December 2025 | 78% | 301 |
| January 2026 | 87% | 269 |
| February 2026 | 83% | 256 |
| March 2026 | 82% | 297 |
| April 2026 | 88% | 289 |
| May 2026 | 86% | 313 |
Same trip, other airports
Keep nerding
Based on 3,624 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.