Route · STL → SEA · 2020–2025 BTS data
St. Louis to Seattle
The STL–SEA corridor (St. Louis, MO → Seattle, WA) runs ahead of the national average, served by 3 carriers across roughly 1,709 miles.
Data updated 2026-06-13
- 82.1%
- On-time
- +3.1 pts
- vs US avg
- 57 min
- Delay when late
- 4,262
- Flights
Cancelled
0.9%
Best Month
Oct 2024 97%
Worst Month
Dec 2025 56%
Distance
1,709 mi
Carriers
3
Monthly Performance
Recent 24 months of route data.
| Period | Flights | Delayed | Cancelled | Diverted | Carriers |
|---|---|---|---|---|---|
| Dec 2025 | 54 | 24 | 1 | 0 | AS |
| Nov 2025 | 50 | 4 | 1 | 0 | AS |
| Oct 2025 | 61 | 7 | 0 | 1 | AS |
| Sep 2025 | 98 | 17 | 0 | 0 | WN,AS |
| Aug 2025 | 111 | 35 | 0 | 1 | WN,AS |
| Jul 2025 | 123 | 40 | 1 | 0 | AS,WN |
| Jun 2025 | 116 | 43 | 1 | 0 | AS,WN |
| May 2025 | 79 | 17 | 1 | 0 | AS |
| Apr 2025 | 59 | 7 | 0 | 0 | AS |
| Mar 2025 | 52 | 8 | 0 | 0 | AS |
| Feb 2025 | 38 | 7 | 0 | 0 | AS |
| Jan 2025 | 34 | 7 | 1 | 0 | AS |
| Dec 2024 | 54 | 8 | 0 | 0 | AS |
| Nov 2024 | 50 | 5 | 0 | 0 | AS |
| Oct 2024 | 60 | 2 | 0 | 0 | AS |
| Sep 2024 | 100 | 13 | 0 | 0 | WN,AS |
| Aug 2024 | 110 | 27 | 0 | 0 | AS,WN |
| Jul 2024 | 122 | 24 | 2 | 0 | AS,WN |
| Jun 2024 | 117 | 31 | 0 | 0 | AS,WN |
| May 2024 | 78 | 27 | 0 | 0 | AS |
| Apr 2024 | 60 | 9 | 1 | 0 | AS |
| Mar 2024 | 56 | 4 | 1 | 0 | AS |
| Feb 2024 | 37 | 4 | 0 | 0 | AS |
| Jan 2024 | 38 | 3 | 5 | 1 | AS |
Cancellation Rate
0.9%
15 of 1,757 flights
Diversion Rate
0.2%
3 of 1,757 flights
Explore origin & destination
On-time and delay data for the airports this route connects.
STL - St. Louis
Full on-time, delay-cause, and seasonal performance for St. Louis, MO.
Origin airport →SEA - Seattle
Full on-time, delay-cause, and seasonal performance for Seattle, WA.
Destination airport →Compare the two airports
See STL 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 STL–SEA.
Routes with a similar on-time rate
What the Data Says About STL to SEA
Bureau of Transportation Statistics records show St. Louis to Seattle (STL to SEA) running a 82.1% on-time rate over 4,262 tracked flights, on the stronger end of a typical domestic pairing. When flights do run late, the average delay is 57.0 minutes. The 1,709-mile corridor is served by 3 carriers, and over the last 24 months 0.9% of 1,757 flights were cancelled, 0.2% diverted.
The monthly split is wide on this route: Oct 2024 posted the strongest performance at 97% on-time, while Dec 2025 came in at just 56% - a 41-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.