Route · IAD → SEA · 2020–2025 BTS data
Washington to Seattle
The IAD–SEA corridor (Washington, DC → Seattle, WA) runs ahead of the national average, served by 9 carriers across roughly 2,306 miles.
Data updated 2026-06-13
- 82%
- On-time
- +3 pts
- vs US avg
- 73 min
- Delay when late
- 10,097
- Flights
Cancelled
1.2%
Best Month
Nov 2024 96%
Worst Month
Dec 2025 49%
Distance
2,306 mi
Carriers
9
Monthly Performance
Recent 24 months of route data.
| Period | Flights | Delayed | Cancelled | Diverted | Carriers |
|---|---|---|---|---|---|
| Dec 2025 | 124 | 63 | 1 | 1 | DL,AS,UA |
| Nov 2025 | 119 | 36 | 3 | 0 | UA,DL,AS |
| Oct 2025 | 156 | 24 | 2 | 0 | AS,UA,DL |
| Sep 2025 | 179 | 14 | 0 | 0 | UA,DL,AS |
| Aug 2025 | 221 | 43 | 1 | 0 | UA,AS,DL |
| Jul 2025 | 245 | 64 | 2 | 1 | AS,UA,DL |
| Jun 2025 | 240 | 67 | 3 | 1 | AS,UA,DL |
| May 2025 | 203 | 33 | 0 | 0 | AS,UA,DL |
| Apr 2025 | 155 | 23 | 0 | 0 | DL,UA,AS |
| Mar 2025 | 116 | 20 | 0 | 0 | AS,DL,UA |
| Feb 2025 | 93 | 33 | 0 | 1 | AS,DL,UA |
| Jan 2025 | 104 | 22 | 1 | 0 | AS,DL,UA |
| Dec 2024 | 135 | 22 | 1 | 1 | AS,DL,UA |
| Nov 2024 | 181 | 8 | 0 | 1 | UA,AS,DL |
| Oct 2024 | 193 | 15 | 1 | 0 | UA,AS,DL |
| Sep 2024 | 230 | 27 | 3 | 0 | UA,AS,DL |
| Aug 2024 | 265 | 53 | 2 | 2 | AS,DL,UA |
| Jul 2024 | 278 | 52 | 5 | 0 | AS,DL,UA |
| Jun 2024 | 270 | 93 | 1 | 2 | AS,DL,UA |
| May 2024 | 226 | 67 | 0 | 0 | AS,DL,UA |
| Apr 2024 | 146 | 31 | 0 | 0 | AS,DL,UA |
| Mar 2024 | 118 | 16 | 0 | 1 | AS,DL,UA |
| Feb 2024 | 95 | 5 | 0 | 1 | AS,DL,UA |
| Jan 2024 | 105 | 10 | 23 | 0 | AS,DL,UA |
Cancellation Rate
1.2%
49 of 4,197 flights
Diversion Rate
0.3%
12 of 4,197 flights
Explore origin & destination
On-time and delay data for the airports this route connects.
IAD - Washington
Full on-time, delay-cause, and seasonal performance for Washington, DC.
Origin airport →SEA - Seattle
Full on-time, delay-cause, and seasonal performance for Seattle, WA.
Destination airport →Compare the two airports
See IAD and SEA side by side on delays, cancellations, and reliability.
Open comparison tool →Similar routes
Other BTS-tracked routes with comparable performance or trip length to IAD–SEA.
Routes with a similar on-time rate
What the Data Says About IAD to SEA
Bureau of Transportation Statistics records show Washington to Seattle (IAD to SEA) running a 82% on-time rate over 10,097 tracked flights, on the stronger end of a typical domestic pairing. When flights do run late, the average delay is 73.4 minutes. The 2,306-mile corridor is served by 9 carriers, and over the last 24 months 1.2% of 4,197 flights were cancelled, 0.3% diverted.
The monthly split is wide on this route: Nov 2024 posted the strongest performance at 96% on-time, while Dec 2025 came in at just 49% - a 46-point swing worth factoring into travel timing.
Frequently Asked Questions
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Data source
Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data. Statistics reflect cumulative performance across all available reporting periods.
Read our methodology - how this data is sourced, computed, and verified.
Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This page aggregates this specific route's on-time performance and monthly trend, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.