Route · DEN → SEA · 2020–2025 BTS data
Denver to Seattle
The DEN–SEA corridor (Denver, CO → Seattle, WA) runs behind the national average, served by 34 carriers across roughly 1,024 miles.
Data updated 2026-06-13
- 77.8%
- On-time
- -1.2 pts
- vs US avg
- 63 min
- Delay when late
- 37,116
- Flights
Cancelled
0.8%
Best Month
Dec 2024 86%
Worst Month
Dec 2025 60%
Distance
1,024 mi
Carriers
34
Monthly Performance
Recent 24 months of route data.
| Period | Flights | Delayed | Cancelled | Diverted | Carriers |
|---|---|---|---|---|---|
| Dec 2025 | 468 | 189 | 4 | 0 | DL,WN,F9,AS,UA |
| Nov 2025 | 464 | 73 | 8 | 0 | UA,DL,F9,AS,WN |
| Oct 2025 | 552 | 111 | 4 | 0 | AS,DL,UA,WN,F9 |
| Sep 2025 | 575 | 123 | 0 | 0 | UA,WN,DL,F9,AS |
| Aug 2025 | 645 | 223 | 4 | 0 | WN,F9,UA,AS,DL |
| Jul 2025 | 670 | 241 | 11 | 0 | AS,UA,WN,DL,F9 |
| Jun 2025 | 643 | 254 | 6 | 1 | AS,UA,WN,DL,F9 |
| May 2025 | 563 | 167 | 4 | 0 | AS,DL,OO,UA,WN,F9 |
| Apr 2025 | 483 | 111 | 1 | 0 | DL,F9,OO,UA,WN,AS |
| Mar 2025 | 472 | 101 | 1 | 1 | AS,OO,UA,WN,DL,F9 |
| Feb 2025 | 409 | 110 | 3 | 0 | AS,OO,UA,WN,DL,F9 |
| Jan 2025 | 447 | 96 | 1 | 1 | AS,OO,UA,WN,DL,F9 |
| Dec 2024 | 469 | 64 | 0 | 1 | AS,DL,F9,OO,UA,WN |
| Nov 2024 | 487 | 89 | 4 | 1 | OO,UA,WN,AS,DL,F9 |
| Oct 2024 | 569 | 82 | 1 | 0 | UA,AS,OO,WN,DL,F9 |
| Sep 2024 | 606 | 114 | 0 | 1 | WN,OO,UA,AS,DL,F9 |
| Aug 2024 | 669 | 206 | 1 | 4 | AS,DL,F9,WN,UA |
| Jul 2024 | 718 | 192 | 13 | 1 | AS,DL,F9,UA,WN |
| Jun 2024 | 684 | 233 | 4 | 2 | AS,DL,F9,UA,WN |
| May 2024 | 599 | 164 | 1 | 0 | AS,DL,F9,UA,WN |
| Apr 2024 | 504 | 121 | 1 | 0 | AS,DL,F9,OO,UA,WN |
| Mar 2024 | 494 | 101 | 8 | 0 | AS,DL,F9,UA,WN |
| Feb 2024 | 449 | 109 | 0 | 0 | AS,DL,F9,UA,WN |
| Jan 2024 | 483 | 126 | 22 | 1 | AS,DL,F9,WN,UA |
Cancellation Rate
0.8%
102 of 13,122 flights
Diversion Rate
0.1%
14 of 13,122 flights
Explore origin & destination
On-time and delay data for the airports this route connects.
DEN - Denver
Full on-time, delay-cause, and seasonal performance for Denver, CO.
Origin airport →SEA - Seattle
Full on-time, delay-cause, and seasonal performance for Seattle, WA.
Destination airport →Compare the two airports
See DEN 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 DEN–SEA.
Routes with a similar on-time rate
What the Data Says About DEN to SEA
The Denver to Seattle corridor (DEN to SEA) posts a 77.8% on-time rate on the lower edge of the average band, based on 37,116 tracked flights. Late flights run 62.9 minutes behind on average. 34 carriers cover the 1,024-mile route; over the last 24 months, 102 of 13,122 flights were cancelled (0.8%) and 0.1% diverted.
The monthly split is wide on this route: Dec 2024 posted the strongest performance at 86% on-time, while Dec 2025 came in at just 60% - a 27-point swing worth factoring into travel timing.
Frequently Asked Questions
How often are flights delayed from DEN to SEA? ▼
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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.