Route · SEA → STL · 2020–2025 BTS data
Seattle to St. Louis
The SEA–STL corridor (Seattle, WA → St. Louis, MO) runs ahead of the national average, served by 3 carriers across roughly 1,709 miles.
Data updated 2026-06-13
- 80.7%
- On-time
- +1.7 pts
- vs US avg
- 49 min
- Delay when late
- 4,258
- Flights
Cancelled
0.4%
Best Month
Mar 2024 91%
Worst Month
Jun 2025 55%
Distance
1,709 mi
Carriers
3
Monthly Performance
Recent 24 months of route data.
| Period | Flights | Delayed | Cancelled | Diverted | Carriers |
|---|---|---|---|---|---|
| Dec 2025 | 54 | 11 | 0 | 0 | AS |
| Nov 2025 | 50 | 8 | 0 | 0 | AS |
| Oct 2025 | 61 | 9 | 0 | 0 | AS |
| Sep 2025 | 98 | 26 | 0 | 0 | WN,AS |
| Aug 2025 | 111 | 41 | 0 | 0 | WN,AS |
| Jul 2025 | 123 | 44 | 0 | 1 | AS,WN |
| Jun 2025 | 116 | 52 | 0 | 2 | AS,WN |
| May 2025 | 79 | 19 | 1 | 0 | AS |
| Apr 2025 | 59 | 6 | 0 | 0 | AS |
| Mar 2025 | 52 | 5 | 0 | 0 | AS |
| Feb 2025 | 38 | 4 | 0 | 0 | AS |
| Jan 2025 | 34 | 6 | 1 | 0 | AS |
| Dec 2024 | 54 | 7 | 0 | 0 | AS |
| Nov 2024 | 50 | 12 | 0 | 0 | AS |
| Oct 2024 | 60 | 8 | 0 | 0 | AS |
| Sep 2024 | 100 | 22 | 0 | 0 | WN,AS |
| Aug 2024 | 110 | 31 | 0 | 1 | AS,WN |
| Jul 2024 | 122 | 43 | 0 | 0 | AS,WN |
| Jun 2024 | 117 | 39 | 0 | 1 | AS,WN |
| May 2024 | 78 | 15 | 0 | 1 | AS |
| Apr 2024 | 60 | 10 | 0 | 0 | AS |
| Mar 2024 | 56 | 5 | 0 | 0 | AS |
| Feb 2024 | 38 | 7 | 0 | 0 | AS |
| Jan 2024 | 37 | 8 | 5 | 0 | AS |
Cancellation Rate
0.4%
7 of 1,757 flights
Diversion Rate
0.3%
6 of 1,757 flights
Explore origin & destination
On-time and delay data for the airports this route connects.
SEA - Seattle
Full on-time, delay-cause, and seasonal performance for Seattle, WA.
Origin airport →STL - St. Louis
Full on-time, delay-cause, and seasonal performance for St. Louis, MO.
Destination airport →Compare the two airports
See SEA and STL side by side on delays, cancellations, and reliability.
Open comparison tool →Similar routes
Other BTS-tracked routes with comparable performance or trip length to SEA–STL.
Routes with a similar on-time rate
What the Data Says About SEA to STL
4,258 tracked flights put the SEA to STL pairing (Seattle to St. Louis) at a 80.7% on-time rate, squarely in line with the wider network. Delays that do occur run 48.6 minutes on average. Across the 1,709-mile route and its 3 carriers, the trailing 24 months show 0.4% cancelled and 0.3% diverted (1,757 flights sampled).
The monthly split is wide on this route: Mar 2024 posted the strongest performance at 91% on-time, while Jun 2025 came in at just 55% - a 36-point swing worth factoring into travel timing.
Frequently Asked Questions
How often are flights delayed from SEA to STL? ▼
What is the cancellation rate for SEA to STL? ▼
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Flight Guides
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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.