SEA to BOS flight delays & on-time performance
Nonstop flights from Seattle–Tacoma International Airport to Boston Logan International Airport · 2,496 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at SEA or BOS right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Seattle (SEA) to Boston (BOS) arrived on time 75% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 1.3% were cancelled, and 8% arrived an hour or more late.
- Delta Air Lines was the most punctual airline here (80% on time); JetBlue was the least (53%).
- Departures scheduled around 7am did best (88% on time); around 10am did worst (50%).
- Saturday was the most reliable day to fly (78% on time) and Thursday the least (73%).
- The largest source of delay minutes was air traffic control & airport congestion (38%).
Which airline is most on time from SEA to BOS?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| Delta Air Lines | 80% | 1.6% | 15 min | 5.9% | 1,034 |
| Alaska Airlines | 75% | 1.0% | 13 min | 6.5% | 1,221 |
| JetBlue | 53% | 1.6% | 42 min | 20.2% | 247 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 7am88%443 flights
- 8am71%238 flights
- 9am75%98 flights
- 10am50%131 flights
- 11am58%205 flights
- 1pm71%34 flights
- 3pm76%516 flights
- 4pm71%73 flights
- 9pm69%35 flights
- 10pm78%339 flights
- 11pm76%366 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday76%1.9% cancelled
- Tuesday76%1.2% cancelled
- Wednesday74%0.6% cancelled
- Thursday73%0.8% cancelled
- Friday77%1.3% cancelled
- Saturday78%0.6% cancelled
- Sunday74%2.7% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Air traffic control & airport congestion38%
- Airline (crew, maintenance, cleaning, fueling)33%
- Late-arriving aircraft23%
- Extreme weather6%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather45%
- Airline (crew, maintenance, cleaning, fueling)42%
- Air traffic control & airport congestion12%
- Security0%
SEA to BOS: common questions
- How often are SEA to BOS flights on time?
- 75% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Seattle to Boston cancelled?
- 1.3% of scheduled flights were cancelled (33 of 2,502).
- How long are typical delays?
- Across all flights the average arrival delay was 17 min (early arrivals count as zero). Flights that were late arrived 62 min behind schedule on average, and 7.6% of flights were an hour or more late.
- How long is taxi time at SEA?
- Flights on this route spent 22 min taxiing from the gate to takeoff on average.
Related routes
Return trip: BOS to SEA — 72% on time
More flights from Seattle
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: SEA → BOS, nonstop flights by US airlines that report to the DOT. How we calculate this.