Sea-Tac (SEA) Flight Delays: Rate, Worst Hours and Live Risk
Sea-Tac (SEA) is ranked 14 of 22 for delays among DelayGuard's guide airports (1 is the highest rate): 21.1% of flights departing SEA arrived 15 or more minutes late across 486,931 flights, January 2023 to December 2025. Alaska Airlines operated 47.0% of those departures, with a 24.5% delay rate of its own. The worst scheduled departure hours are 1 AM (27.2%) and 10 PM (26.7%); 5 AM is the best at 7.2%. 0.96% of scheduled SEA departures were cancelled in 2024 to 2025.
These figures are historical US domestic rates, not a forecast for one departure. Use the delay risk check for your flight before you book.
Delay window: January 2023 to December 2025. Cancellation window: 2024 to 2025. Last updated: 2026-10-18. Delayed means a flight arrived 15 or more minutes after its scheduled arrival, the BTS and DOT on-time standard. Cancelled and diverted flights are excluded from delay rates. Historical BTS figures are separate from DelayGuard's per-flight model probability and from live FAA, weather and ground-delay status.
Layover buffer
Chance an inbound arrival is 45+ min late at SEA: 7.28%.
35,419 of 486,693 arrivals, January 2023 to December 2025. Not a missed-connection rate.
Flight delays today at SEA
FAA now: No FAA program
Tomorrow: Higher than usual
October delay rate: 16.1%
FAA now is the current National Airspace System program.
Historical delay rate (15+ min late) at SEA
Sample size: 486,931 flights, window: January 2023 to December 2025. Delay rate 21.1%. Source: Bureau of Transportation Statistics (BTS). Cancellation rate 0.96% of 328,559 scheduled flights, 2024 to 2025.
Why SEA runs the way it does
Alaska Airlines flew 47.0% of SEA departures in the window, and its flights ran 24.5% late against 21.1% for the airport as a whole. With one carrier that large, SEA's delay record largely follows how Alaska Airlines runs its schedule.
SEA delays peak in June (26.4%), July (25.9%) and August (25.0%) and are lowest in October (16.1%). That shape is consistent with the summer thunderstorm season, when convective weather builds through the afternoon and slows arrivals and departures.
Delays build through the day: 13.2% of flights scheduled before 8 AM ran late against 24.4% after 8 PM. That is the pattern BTS describes as late-arriving aircraft, where a previous flight with the same aircraft arriving late makes the next departure late.
Best and worst times to fly from SEA
| Hour | Delayed 15+ min | Flights |
|---|---|---|
| 12 AM | 18.5% | 2,092 |
| 1 AM | 27.2% | 276 |
| 5 AM | 7.2% | 9,182 |
| 6 AM | 9.5% | 22,295 |
| 7 AM | 16.2% | 41,273 |
| 8 AM | 17.4% | 30,295 |
| 9 AM | 18.1% | 35,999 |
| 10 AM | 22.3% | 27,827 |
| 11 AM | 24.9% | 41,840 |
| 12 PM | 23.0% | 23,781 |
| 1 PM | 22.4% | 27,552 |
| 2 PM | 22.5% | 16,116 |
| 3 PM | 21.2% | 34,688 |
| 4 PM | 22.7% | 14,442 |
| 5 PM | 24.2% | 32,812 |
| 6 PM | 25.3% | 20,385 |
| 7 PM | 22.1% | 28,945 |
| 8 PM | 25.6% | 13,125 |
| 9 PM | 25.2% | 27,333 |
| 10 PM | 26.7% | 16,956 |
| 11 PM | 20.4% | 19,717 |
SEA delays and cancellations by month
| Month | Delayed 15+ min | Flights | Cancelled |
|---|---|---|---|
| Jan | 20.4% | 34,160 | 4.54% |
| Feb | 19.6% | 32,431 | 0.78% |
| Mar | 18.9% | 37,718 | 0.34% |
| Apr | 19.2% | 38,210 | 0.19% |
| May | 22.0% | 42,508 | 0.42% |
| Jun | 26.4% | 45,165 | 0.54% |
| Jul | 25.9% | 47,673 | 1.53% |
| Aug | 25.0% | 47,486 | 0.73% |
| Sep | 19.2% | 44,178 | 0.31% |
| Oct | 16.1% | 41,637 | 0.77% |
| Nov | 16.4% | 37,778 | 1.03% |
| Dec | 20.8% | 37,987 | 0.77% |
Airlines at SEA
| Airline | Share of departures | Delayed 15+ min | Flights | Cancelled |
|---|---|---|---|---|
| Alaska Airlines | 47.0% | 24.5% | 229,080 | 1.29% |
| Delta Air Lines | 19.8% | 16.7% | 96,302 | 0.57% |
| SkyWest Airlines | 16.5% | 14.8% | 80,146 | 0.45% |
| United Airlines | 5.5% | 17.7% | 26,646 | 1.19% |
| Southwest Airlines | 5.0% | 24.7% | 24,395 | 0.26% |
| American Airlines | 3.6% | 21.0% | 17,438 | 1.57% |
| Frontier Airlines | 0.8% | 30.6% | 4,040 | 1.85% |
| Hawaiian Airlines | 0.6% | 33.1% | 3,139 | 1.51% |
| JetBlue Airways | 0.5% | 37.2% | 2,512 | 1.15% |
| Spirit Airlines (ceased 2 May 2026) | 0.5% | 24.4% | 2,331 | 0.90% |
Regional operators are reported separately from the airline brands they fly for.
Routes from SEA
| Route | Delayed 15+ min | Flights | Cancelled | Link |
|---|---|---|---|---|
| SEA to LAX | 18.0% | 22,227 | 0.93% | Route page |
| SEA to ANC | 23.9% | 21,792 | 0.97% | Predict |
| SEA to PHX | 20.8% | 21,373 | 0.66% | Route page |
| SEA to SFO | 27.6% | 19,967 | 1.14% | Route page |
| SEA to DEN | 22.7% | 19,511 | 0.87% | Route page |
| SEA to LAS | 23.4% | 19,186 | 0.87% | Route page |
| SEA to PDX | 19.0% | 16,136 | 0.79% | Predict |
| SEA to GEG | 19.9% | 15,387 | 0.63% | Predict |
| SEA to ORD | 22.4% | 15,131 | 1.00% | Route page |
| SEA to DFW | 24.7% | 14,123 | 1.72% | Route page |
| SEA to SJC | 18.0% | 13,800 | 0.90% | Predict |
| SEA to SAN | 20.9% | 13,663 | 1.22% | Predict |
| SEA to SMF | 20.3% | 12,461 | 0.46% | Predict |
| SEA to BOI | 15.9% | 12,211 | 0.22% | Predict |
| SEA to SNA | 15.0% | 11,934 | 0.89% | Predict |
- Summer thunderstorm delays: which airports suffer most
- Thanksgiving and Christmas 2026 flight delay guide
- US airline cancellation rates
Questions
- How often are flights delayed at SEA?
- 21.1% of flights departing SEA arrived 15 or more minutes late across 486,931 flights, January 2023 to December 2025 (BTS). Across all US domestic flights in the data, the rate is 21.2%.
- What is the best time to fly from SEA?
- Early departures run best. 5 AM flights ran 7.2% late (9,182 flights), 6 AM flights ran 9.5% late (22,295 flights) and 7 AM flights ran 16.2% late (41,273 flights). The worst hours are 1 AM (27.2%), 10 PM (26.7%) and 8 PM (25.6%).
- Which month is worst for delays at SEA?
- June has the highest delay rate at 26.4%. October is the lowest at 16.1%.
- Which airline has the best on-time record at SEA?
- Among carriers still flying with at least 5,000 flights from SEA, SkyWest Airlines has the lowest delay rate at 14.8% (80,146 flights). Southwest Airlines is highest at 24.7%. Regional operators such as SkyWest are reported separately from the airline brands they fly for.
- How often are SEA flights cancelled?
- 0.96% of 328,559 scheduled departures from SEA were cancelled in 2024 to 2025. The US figure over the same period is 1.41%. See the full ranking on the cancellation rates page.
- Does DelayGuard show live delays at SEA?
- Yes. The live module on this page shows DelayGuard's hourly risk score and any active FAA ground stop or ground delay program. It is separate from the historical BTS figures above. For a specific flight, the predictor gives a model probability that combines history, weather and FAA data.
- Why does SEA have delays?
- Alaska Airlines flew 47.0% of SEA departures in the window, and its flights ran 24.5% late against 21.1% for the airport as a whole. With one carrier that large, SEA's delay record largely follows how Alaska Airlines runs its schedule. SEA delays peak in June (26.4%), July (25.9%) and August (25.0%) and are lowest in October (16.1%). That shape is consistent with the summer thunderstorm season, when convective weather builds through the afternoon and slows arrivals and departures.