Route Reliability
Seattle → Washington
SEA–IAD · 2,305 miles · Seattle–Tacoma International Airport to Washington Dulles International Airport
- 82%
- Arrive within 15 minutes
- 1 min
- Average arrival delay
- 0.7%
- Cancelled
- 1,928
- Flights in the data
Data through May 2026.
Who flies it best
Ranked by on-time arrivals. Historical results, not predictions.
- 1.United Airlines86%732 flights
- 2.Alaska Airlines80%835 flights
- 3.Delta Air Lines78%361 flights
What the data says
Morning flights do better here.
SEA–IAD flights departing between 6–9 AM arrived on time 91% of the time, versus 77% between 3–6 PM.
Friday is doing you no favors.
SEA–IAD flights arrived on time 86% of the time on Tuesdays. On Fridays: 78%.
United Airlines runs this route best.
United Airlines arrived on time 86% of the time on this route; Delta Air Lines managed 78%.
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
- Mon83%(282 flights)
- Tue86%(258 flights)
- Wed86%(258 flights)
- Thu83%(278 flights)
- Fri78%(281 flights)
- Sat78%(261 flights)
- Sun79%(286 flights)
- 6–9 AM91%(450 flights)
- 9 AM–12 PM79%(266 flights)
- 12–3 PM85%(131 flights)
- 3–6 PM77%(414 flights)
- 9 PM–12 AM79%(643 flights)
Jun 77% → May 88% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 77% | 234 |
| July 2025 | 71% | 242 |
| August 2025 | 73% | 221 |
| September 2025 | 88% | 178 |
| October 2025 | 85% | 153 |
| November 2025 | 86% | 118 |
| December 2025 | 88% | 124 |
| January 2026 | 84% | 99 |
| February 2026 | 87% | 93 |
| March 2026 | 84% | 115 |
| April 2026 | 89% | 127 |
| May 2026 | 88% | 200 |
Same trip, other airports
Keep nerding
Based on 1,928 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.