Delta Air Lines IAD to SEA on-time performance
Delta Air Lines nonstop flights from Washington to Seattle · Aug 2025 – Jul 2026
On-time arrivals
77%
arrived < 15 min late
Cancelled
1.4%
5 flights
Avg arrival delay
23 min
93 min when late
Rank on route
#2 of 3
route average 78% on time
Key facts
- Delta Air Lines flights on IAD to SEA arrived on time 77% of the time in Aug 2025 – Jul 2026.
- 1.4% were cancelled, and 8% arrived an hour or more late.
- That ranks #2 of 3 airlines on this route, which averaged 78% on time overall.
- The largest source of delay minutes was airline (crew, maintenance, cleaning, fueling) (70%).
On-time trend by month
Why this airline's flights were late
- Airline (crew, maintenance, cleaning, fueling)70%
- Air traffic control & airport congestion23%
- Extreme weather7%
- Late-arriving aircraft1%
- Security0%
Other airlines on IAD to SEA
- Alaska Airlines75% on time · 13 min avg delay
- United Airlines81% on time · 13 min avg delay
Full IAD to SEA comparison →
Delta Air Lines on-time record across all routes →
361 Delta Air Lines flights tracked on this route; 5 cancelled, 1 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.