Delta Air Lines BOS to SEA on-time performance
Delta Air Lines nonstop flights from Boston to Seattle · Aug 2025 – Jul 2026
On-time arrivals
73%
arrived < 15 min late
Cancelled
1.4%
15 flights
Avg arrival delay
17 min
56 min when late
Rank on route
#2 of 3
route average 72% on time
Key facts
- Delta Air Lines flights on BOS to SEA arrived on time 73% of the time in Aug 2025 – Jul 2026.
- 1.4% were cancelled, and 6% arrived an hour or more late.
- That ranks #2 of 3 airlines on this route, which averaged 72% on time overall.
- The largest source of delay minutes was air traffic control & airport congestion (36%).
On-time trend by month
Why this airline's flights were late
- Air traffic control & airport congestion36%
- Airline (crew, maintenance, cleaning, fueling)34%
- Late-arriving aircraft28%
- Extreme weather2%
- Security0%
Other airlines on BOS to SEA
- Alaska Airlines71% on time · 16 min avg delay
- JetBlue79% on time · 16 min avg delay
Full BOS to SEA comparison →
Delta Air Lines on-time record across all routes →
1,035 Delta Air Lines flights tracked on this route; 15 cancelled, 3 diverted.
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. How we calculate this.