Best Time to Fly DEN to SEA: On-Time Stats by Hour & Airline
Denver International → Seattle/Tacoma International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 74.7% of Denver (DEN) to Seattle (SEA) flights arrived on time (6,317 scheduled flights). That is 3.0 points below the national average of 77.6%.
United Airlines was the most punctual of the 6 airlines on the route at 80.7%, while Southwest Airlines trailed at 61.1%.
November has been the best month (83% on time) and Sunday the weakest day of the week (73%).
0.6% of flights were cancelled, versus 1.8% nationally.
DEN to SEA on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| United Airlines | 80.7% | 56 min | 0.5% | 1,906 |
| Frontier Airlines | 79.5% | 55 min | 1.4% | 431 |
| Delta Air Lines | 79.2% | 86 min | 0.9% | 868 |
| SkyWest Airlines | 75.8% | 70 min | 0.5% | 220 |
| Alaska Airlines | 74.9% | 57 min | 0.8% | 1,551 |
| Southwest Airlines | 61.1% | 46 min | 0.2% | 1,341 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly DEN to SEA
On-time arrival % by scheduled departure hour (local time), 12,804 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 12am–1am | Limited data | 2 | |
| 5am–6am | 81.6% | 0.0% | 49 |
| 6am–7am | 88.7% | 0.5% | 1,333 |
| 7am–8am | 88.8% | 0.1% | 1,025 |
| 8am–9am | 80.8% | 0.8% | 995 |
| 9am–10am | 77.0% | 0.6% | 315 |
| 10am–11am | 80.0% | 0.6% | 366 |
| 11am–12pm | 80.7% | 0.4% | 927 |
| 12pm–1pm | 77.3% | 1.1% | 917 |
| 1pm–2pm | 81.8% | 0.1% | 761 |
| 2pm–3pm | 69.9% | 0.4% | 237 |
| 3pm–4pm | 69.7% | 0.5% | 814 |
| 4pm–5pm | 72.7% | 0.2% | 829 |
| 5pm–6pm | 59.2% | 1.1% | 441 |
| 6pm–7pm | 60.0% | 0.5% | 567 |
| 7pm–8pm | 66.5% | 0.4% | 1,664 |
| 8pm–9pm | 60.0% | 0.8% | 513 |
| 9pm–10pm | 63.1% | 0.7% | 721 |
| 10pm–11pm | 59.2% | 2.1% | 326 |
| 11pm–12am | Limited data | 2 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on DEN to SEA
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 74.5% | -2.7 pts | 0.0% | 224 |
| Christmas & New Year (Dec 20 - Jan 3) | 76.4% | -0.8 pts | 0.2% | 485 |
| Summer peak (Jun 15 - Aug 15) | 65.3% | -11.9 pts | 1.0% | 2,706 |
| All other days | 77.2% | — | 0.5% | 9,389 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).