Route · DEN → SEA · 2020–2025 BTS data
Denver to Seattle
According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), DEN to SEA (Denver to Seattle) ranks #49 of 4927 tracked domestic routes by total flights (most flights = #1).
Data updated 2026-06-13
- 77.8%
- On-time
- -1.2 pts
- vs US avg
- 63 min
- Delay when late
- 37,116
- Flights
- #49 of 4927
- Corpus placement
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 |
DEN–SEA seasonal on-time pattern
Best: October (84.4%) · weakest: June (70.3%)
Strongest calendar month
October
84.4% on-time · ~552 flights/mo
Busiest calendar month
August
~617 flights/mo avg
Weakest calendar month
June
70.3% on-time · ~569 flights/mo
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.
DEN on-time profileSEA - Seattle
Full on-time, delay-cause, and seasonal performance for Seattle, WA.
SEA on-time profileCompare the two airports
See DEN and SEA side by side on delays, cancellations, and reliability.
Compare DEN vs SEAOrigin-hub reliability standing
Mid-pack among DEN departures
From DEN, this corridor sits with 133 other 75–85% on-time routes out of 168 tracked departures, not the hub's reliability leaders (8 at ≥85%) and not the softest ( 27 below 75%). Destination: Seattle · fleet on-time rank #3887 of 4927.
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.
On the multi-year calendar, DEN–SEA peaks in October at 84.4% on-time while August carries the heaviest traffic (~617 flights per month) ; the softest month is June at 70.3%, a 14.1-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.
Frequently Asked Questions
Where does DEN to SEA rank among US routes by traffic? ▼
How often are flights delayed from DEN to SEA? ▼
What is the cancellation rate for DEN to SEA? ▼
How far is the flight from DEN to SEA? ▼
When is the best time to fly from DEN to SEA? ▼
Airports on this route
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.
Using DEN–SEA data
DEN–SEA is mid-pack at 77.8% on-time; month and carrier mix move more than the corridor headline.
- Compare DEN and SEA airport profiles: delay causes and top routes differ even on the same corridor. DEN airport
- If your dates flex, October (84.4% on-time) beats June (70.3%) on this corridor. Seasonal chart
- 4 other routes post a similar 77.8% on-time rate; compare before you commit to this pairing. Similar routes
On-time rate reflects the BTS historical average across all reporting carriers on this origin–destination pair, not any single flight or booking recommendation.
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.