Seattle/Tacoma International (SEA) Delays and On-Time Departures
Seattle, WA · ranked 221st of 333 airports for on-time departures
Data through July 2026 · Last updated October 18, 2026
78.9% of the 164,821 flights scheduled to depart Seattle (SEA) in the last 12 months left on time, 1.5 points above the US average of 77.4%.
That ranks 221st of 333 US airports tracked on this site, with 0.9% of departures cancelled.
Among airlines at Seattle (SEA), SkyWest Airlines left on time most often (86.9%).
Over 24 months, Tuesday was the most reliable day (83% on time) and July the worst month (73%).
Best time of day to fly out of Seattle (SEA)
On-time departure % by scheduled departure hour (local time), last 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 12am–1am | 76.9% | 1.3% | 1,455 |
| 1am–2am | 74.0% | 0.8% | 120 |
| 5am–6am | 94.0% | 0.7% | 5,323 |
| 6am–7am | 92.3% | 1.0% | 11,176 |
| 7am–8am | 89.5% | 1.0% | 26,793 |
| 8am–9am | 87.8% | 1.0% | 23,963 |
| 9am–10am | 83.8% | 0.7% | 24,344 |
| 10am–11am | 77.4% | 0.7% | 20,302 |
| 11am–12pm | 74.0% | 0.7% | 29,725 |
| 12pm–1pm | 77.0% | 0.7% | 15,062 |
| 1pm–2pm | 77.7% | 0.6% | 18,847 |
| 2pm–3pm | 77.5% | 0.7% | 11,393 |
| 3pm–4pm | 76.8% | 0.8% | 22,621 |
| 4pm–5pm | 76.2% | 0.7% | 10,658 |
| 5pm–6pm | 75.9% | 0.7% | 23,036 |
| 6pm–7pm | 75.0% | 0.7% | 13,938 |
| 7pm–8pm | 78.1% | 0.5% | 19,444 |
| 8pm–9pm | 71.1% | 0.7% | 10,124 |
| 9pm–10pm | 76.1% | 0.9% | 17,050 |
| 10pm–11pm | 72.3% | 0.8% | 10,980 |
| 11pm–12am | 76.2% | 1.2% | 12,883 |
Airlines at SEA ranked by on-time departures
Last 12 months. Airlines with fewer than 30 departures are marked “limited data”.
| Airline | On-time departures | On-time arrivals | Cancelled | Departures |
|---|---|---|---|---|
| SkyWest Airlines | 86.9% | 85.6% | 0.7% | 28,770 |
| Envoy Air | 85.7% | 85.6% | 0.0% | 754 |
| Delta Air Lines | 82.3% | 81.1% | 1.1% | 32,324 |
| United Airlines | 82.0% | 80.1% | 0.8% | 8,748 |
| Alaska Airlines | 76.4% | 78.1% | 0.9% | 76,779 |
| Frontier Airlines | 75.7% | 75.8% | 2.1% | 1,404 |
| American Airlines | 75.2% | 79.5% | 2.0% | 6,702 |
| Southwest Airlines | 64.0% | 69.6% | 0.4% | 8,098 |
| Hawaiian Airlines | 61.0% | 63.3% | 1.2% | 817 |
| JetBlue | 53.1% | 61.5% | 2.9% | 413 |
| Spirit Airlines | Limited data | 12 | ||
80%+ good 70–79.9% fair <70% poor
Best day to fly out of SEA
On-time departures by day, 24 months.
Best month to fly out of SEA
On-time departures by month, 24 months.
Holiday travel at Seattle (SEA)
On-time departures during holiday periods compared with all other days, last 24 months.
| Period | On-time departures | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 80.7% | -0.7 pts | 0.6% | 5,809 |
| Christmas & New Year (Dec 20 - Jan 3) | 74.6% | -6.7 pts | 0.9% | 12,445 |
| Summer peak (Jun 15 - Aug 15) | 72.5% | -8.9 pts | 0.9% | 65,504 |
| All other days | 81.4% | — | 0.7% | 245,479 |
Monthly on-time departure trend at SEA
On-time departure % each month, with the 12-month US average for reference.
Routes from Seattle (SEA)
Every route from SEA with its own page, by number of flights (last 12 months, on-time arrivals).