Route
IAD → SEA
Washington Dulles International Airport Seattle–Tacoma International Airport
How punctual is this route?
- On-time arrivals
- 77.7%
- Less than 15 minutes late
- Cancelled
- 1.0%
- Of scheduled flights
- Average delay when late
- 69 min
- Flights arriving 15+ minutes late
- Flights tracked
- 1,821
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 41%
- Air traffic control & airport 32%
- Late-arriving aircraft 16%
- Extreme weather 9%
- Security 1%
Share of delay minutes airlines attributed to each cause (BTS).
Show as table
| Month | On time | Flights |
|---|---|---|
| September 2025 | 92.2% | 179 |
| October 2025 | 84.4% | 156 |
| November 2025 | 69.0% | 119 |
| December 2025 | 48.4% | 124 |
| January 2026 | 74.0% | 103 |
| February 2026 | 75.8% | 93 |
| March 2026 | 54.4% | 117 |
| April 2026 | 82.7% | 128 |
| May 2026 | 86.1% | 201 |
| June 2026 | 78.5% | 198 |
| July 2026 | 82.8% | 212 |
| August 2026 | 80.6% | 191 |
Source: U.S. DOT Bureau of Transportation Statistics on-time data, September 2025 – August 2026. Covers flights operated by reporting U.S. carriers. About our data
Airlines on this route
| Airline | Flights | On time | Cancelled | Avg. delay when late |
|---|---|---|---|---|
| Alaska Airlines | 835 | 75.4% | 1.2% | 57 min |
| United Airlines | 625 | 81.3% | 0.5% | 73 min |
| Delta Air Lines | 361 | 76.6% | 1.4% | 94 min |
Delay odds by flight
How often each flight number arrived 15 or more minutes late over the last year.
-
DL1015
23% late · 349 flights
-
UA326
24% late · 254 flights
-
AS351
24% late · 244 flights
-
AS737
42% late · 160 flights
-
AS409
33% late · 131 flights
-
AS375
10% late · 116 flights
-
UA2101
9% late · 92 flights
-
UA2241
13% late · 82 flights
-
AS361
7% late · 70 flights
-
AS406
20% late · 68 flights
-
UA1914
2% late · 47 flights
-
UA1159
22% late · 37 flights
-
AS416
12% late · 33 flights
-
UA1303
43% late · 24 flights
-
UA2799
10% late · 21 flights
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