Route · BOS → SEA · 2020–2025 BTS data
Boston to Seattle
The BOS–SEA corridor (Boston, MA → Seattle, WA) runs ahead of the national average, served by 9 carriers across roughly 2,496 miles.
Data updated 2026-06-13
- 81.2%
- On-time
- +2.2 pts
- vs US avg
- 70 min
- Delay when late
- 13,744
- Flights
Cancelled
0.9%
Best Month
Feb 2024 95%
Worst Month
Dec 2025 42%
Distance
2,496 mi
Carriers
9
Monthly Performance
Recent 24 months of route data.
| Period | Flights | Delayed | Cancelled | Diverted | Carriers |
|---|---|---|---|---|---|
| Dec 2025 | 161 | 93 | 3 | 5 | DL,AS |
| Nov 2025 | 163 | 36 | 1 | 0 | AS,DL |
| Oct 2025 | 228 | 46 | 2 | 0 | AS,B6,DL |
| Sep 2025 | 229 | 36 | 0 | 1 | DL,AS,B6 |
| Aug 2025 | 271 | 46 | 0 | 0 | AS,B6,DL |
| Jul 2025 | 274 | 103 | 6 | 1 | AS,B6,DL |
| Jun 2025 | 255 | 88 | 1 | 0 | AS,B6,DL |
| May 2025 | 227 | 38 | 2 | 0 | AS,B6,DL |
| Apr 2025 | 195 | 37 | 0 | 1 | AS,B6,DL |
| Mar 2025 | 192 | 28 | 1 | 0 | AS,B6,DL |
| Feb 2025 | 145 | 42 | 6 | 2 | AS,B6,DL |
| Jan 2025 | 151 | 22 | 0 | 0 | AS,B6,DL |
| Dec 2024 | 186 | 39 | 0 | 1 | AS,B6,DL |
| Nov 2024 | 186 | 22 | 0 | 0 | B6,AS,DL |
| Oct 2024 | 232 | 47 | 0 | 0 | AS,DL,B6 |
| Sep 2024 | 234 | 27 | 2 | 0 | AS,B6,DL |
| Aug 2024 | 274 | 87 | 3 | 0 | AS,B6,DL |
| Jul 2024 | 271 | 71 | 7 | 0 | AS,B6,DL |
| Jun 2024 | 252 | 124 | 3 | 0 | AS,B6,DL |
| May 2024 | 237 | 50 | 0 | 0 | AS,B6,DL |
| Apr 2024 | 210 | 38 | 1 | 0 | AS,B6,DL |
| Mar 2024 | 188 | 24 | 1 | 1 | AS,B6,DL |
| Feb 2024 | 153 | 7 | 1 | 0 | AS,B6,DL |
| Jan 2024 | 158 | 32 | 5 | 1 | AS,B6,DL |
Cancellation Rate
0.9%
45 of 5,072 flights
Diversion Rate
0.3%
13 of 5,072 flights
Explore origin & destination
On-time and delay data for the airports this route connects.
BOS - Boston
Full on-time, delay-cause, and seasonal performance for Boston, MA.
Origin airport →SEA - Seattle
Full on-time, delay-cause, and seasonal performance for Seattle, WA.
Destination airport →Compare the two airports
See BOS 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 BOS–SEA.
Routes with a similar on-time rate
What the Data Says About BOS to SEA
13,744 tracked flights put the BOS to SEA pairing (Boston to Seattle) at a 81.2% on-time rate, squarely in line with the wider network. Delays that do occur run 69.7 minutes on average. Across the 2,496-mile route and its 9 carriers, the trailing 24 months show 0.9% cancelled and 0.3% diverted (5,072 flights sampled).
The monthly split is wide on this route: Feb 2024 posted the strongest performance at 95% on-time, while Dec 2025 came in at just 42% - a 53-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.