Best Time to Fly ATL to SEA: On-Time Stats by Hour & Airline
Hartsfield-Jackson Atlanta International → Seattle/Tacoma International
Data through July 2026 · Last updated October 18, 2026
3,278 flights were scheduled from Atlanta (ATL) to Seattle (SEA) in the last 12 months, and 76.8% of those that flew arrived on time, 0.8 points below the US average of 77.6%.
Among 2 airlines, Delta Air Lines led with 77.6% on time and Alaska Airlines was last with 74.5%.
Over 24 months, Saturday was the most reliable day (82% on time) and July the worst month (73%).
The cancellation rate was 0.6% (US average 1.8%).
ATL 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 |
|---|---|---|---|---|
| Delta Air Lines | 77.6% | 55 min | 0.5% | 2,380 |
| Alaska Airlines | 74.5% | 55 min | 1.0% | 898 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly ATL to SEA
On-time arrival % by scheduled departure hour (local time), 6,646 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 90.1% | 0.0% | 111 |
| 7am–8am | 85.9% | 1.0% | 1,150 |
| 8am–9am | 73.7% | 0.5% | 218 |
| 9am–10am | 80.9% | 0.5% | 974 |
| 10am–11am | 85.1% | 0.0% | 74 |
| 11am–12pm | 83.5% | 0.4% | 481 |
| 12pm–1pm | 84.9% | 0.3% | 385 |
| 1pm–2pm | 89.6% | 0.0% | 308 |
| 2pm–3pm | 86.4% | 0.0% | 176 |
| 3pm–4pm | 83.5% | 0.6% | 319 |
| 4pm–5pm | 73.7% | 0.4% | 560 |
| 5pm–6pm | 67.5% | 0.6% | 161 |
| 6pm–7pm | 74.8% | 0.0% | 343 |
| 7pm–8pm | 63.4% | 1.3% | 786 |
| 8pm–9pm | 69.1% | 0.0% | 97 |
| 9pm–10pm | 80.4% | 0.8% | 503 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on ATL 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) | 74.8% | -6.2 pts | 0.8% | 120 |
| Christmas & New Year (Dec 20 - Jan 3) | 78.5% | -2.4 pts | 0.8% | 264 |
| Summer peak (Jun 15 - Aug 15) | 74.1% | -6.9 pts | 0.7% | 1,396 |
| All other days | 81.0% | — | 0.5% | 4,866 |
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).