Route · SEA → BOS · 2020–2025 BTS data
Seattle to Boston
The SEA–BOS corridor (Seattle, WA → Boston, MA) runs behind the national average, served by 9 carriers across roughly 2,496 miles.
Data updated 2026-06-13
- 77.2%
- On-time
- -1.8 pts
- vs US avg
- 66 min
- Delay when late
- 13,741
- Flights
Cancelled
0.8%
Best Month
Apr 2025 88%
Worst Month
Jul 2025 60%
Distance
2,496 mi
Carriers
9
Monthly Performance
Recent 24 months of route data.
| Period | Flights | Delayed | Cancelled | Diverted | Carriers |
|---|---|---|---|---|---|
| Dec 2025 | 161 | 22 | 2 | 0 | DL,AS |
| Nov 2025 | 164 | 27 | 1 | 6 | AS,DL |
| Oct 2025 | 227 | 62 | 2 | 0 | AS,B6,DL |
| Sep 2025 | 229 | 75 | 0 | 0 | DL,AS,B6 |
| Aug 2025 | 270 | 94 | 0 | 2 | AS,B6,DL |
| Jul 2025 | 274 | 109 | 4 | 1 | AS,B6,DL |
| Jun 2025 | 255 | 75 | 2 | 0 | AS,B6,DL |
| May 2025 | 228 | 85 | 2 | 0 | AS,B6,DL |
| Apr 2025 | 196 | 23 | 1 | 0 | AS,B6,DL |
| Mar 2025 | 191 | 31 | 1 | 1 | AS,B6,DL |
| Feb 2025 | 146 | 25 | 5 | 0 | AS,B6,DL |
| Jan 2025 | 150 | 25 | 1 | 0 | AS,B6,DL |
| Dec 2024 | 185 | 51 | 0 | 1 | AS,B6,DL |
| Nov 2024 | 187 | 24 | 0 | 0 | B6,AS,DL |
| Oct 2024 | 230 | 36 | 0 | 0 | AS,DL,B6 |
| Sep 2024 | 234 | 59 | 0 | 0 | AS,B6,DL |
| Aug 2024 | 273 | 97 | 2 | 0 | AS,B6,DL |
| Jul 2024 | 271 | 71 | 5 | 0 | AS,B6,DL |
| Jun 2024 | 252 | 57 | 1 | 1 | AS,B6,DL |
| May 2024 | 238 | 63 | 2 | 1 | AS,B6,DL |
| Apr 2024 | 210 | 65 | 0 | 0 | AS,B6,DL |
| Mar 2024 | 189 | 37 | 0 | 0 | AS,B6,DL |
| Feb 2024 | 154 | 33 | 0 | 0 | AS,B6,DL |
| Jan 2024 | 157 | 43 | 10 | 0 | AS,B6,DL |
Cancellation Rate
0.8%
41 of 5,071 flights
Diversion Rate
0.3%
13 of 5,071 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 →BOS - Boston
Full on-time, delay-cause, and seasonal performance for Boston, MA.
Destination airport →Compare the two airports
See SEA and BOS 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–BOS.
Routes with a similar on-time rate
What the Data Says About SEA to BOS
The Seattle to Boston corridor (SEA to BOS) posts a 77.2% on-time rate on the lower edge of the average band, based on 13,741 tracked flights. Late flights run 66.4 minutes behind on average. 9 carriers cover the 2,496-mile route; over the last 24 months, 41 of 5,071 flights were cancelled (0.8%) and 0.3% diverted.
The monthly split is wide on this route: Apr 2025 posted the strongest performance at 88% on-time, while Jul 2025 came in at just 60% - a 28-point swing worth factoring into travel timing.
Frequently Asked Questions
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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.