Route reliability
Atlanta (ATL) to Seattle (SEA): which airline is most on time?
On-time arrivals, cancellations and long delays for every airline that reported nonstop flights from Atlanta, GA (ATL) to Seattle, WA (SEA), September 2025 to August 2026.
Atlanta, GASeattle, WA
Route at a glance · September 2025 to August 2026
ATL to SEA
Atlanta, GA to Seattle, WA
- On time
- 76.0%vs 75.6% U.S. average About average
- Cancelled
- 0.7%vs 1.9% U.S. average Better than average
- 60+ min late
- 5.7%vs 8.1% U.S. average Better than average
- Scheduled flights
- 3,297in 12 months2 airlines
- Most reliable airline
- Delta Air Lines76.1% on time · 2,404 flights
On time about as often as the U.S. average, with fewer cancellations.
Airlines on this route
Ranked by on-time arrival
| Airline | On time | Cancelled | 60+ min late | Avg delay when late | Diverted | Flights |
|---|---|---|---|---|---|---|
| 1. Delta Air Lines Most reliable | 76.1% | 0.6% | 5.6% | 58 min | 0.3% | 2,404 |
| 2. Alaska Airlines | 75.6% | 1.0% | 5.9% | 55 min | 0.1% | 893 |
On time = arrived within 15 minutes of schedule. Avg delay when late = average arrival delay of flights 15+ minutes late. "Most reliable" needs at least 300 flights in 12 months. Tap a heading to sort.
What this means
Delta Air Lines has the strongest record on this route.
- Delta Air Lines had the best on-time record from Atlanta (ATL) to Seattle (SEA): 76.1% of its 2,404 scheduled flights arrived within 15 minutes of schedule, compared with 75.6% for Alaska Airlines. The gap is small, so treat the airlines as roughly equal on punctuality.
- 0.7% of flights on this route were cancelled (about 1 in 143), 1.2 points lower than the U.S. average of 1.9%.
- 5.7% of flights, about 1 in 18, arrived an hour or more late. When a flight was late (15+ minutes), the average arrival delay was 57 min.
- Overall, 76.0% of flights on this route arrived on time, about the same as the U.S. average of 75.6%.
- Over the last 3 years, November was the most reliable month on this route (89.6% on time) and July the least reliable (69.2%).
- Cancellations peaked in January, when 3.8% of flights were cancelled.
- Flights scheduled to depart 1 pm to 2 pm were the most punctual (85.1% on time); flights scheduled to depart 7 pm to 8 pm were the least (62.9%).
- In the other direction, Seattle (SEA) to Atlanta (ATL), 83.0% of flights were on time and 0.7% were cancelled. Compare airlines SEA to ATL.
Best and worst months to fly ATL to SEA
Share of scheduled flights on time 12-month average 76.0%
Show as table
| Period | On time | Flights |
|---|---|---|
| January | 76.0% | 662 |
| February | 79.3% | 588 |
| March | 80.2% | 706 |
| April | 83.7% | 765 |
| May | 75.1% | 899 |
| June | 73.1% | 1,000 |
| July | 69.2% | 1,072 |
| August | 77.3% | 1,023 |
| September | 87.7% | 935 |
| October | 88.5% | 908 |
| November | 89.6% | 807 |
| December | 80.5% | 812 |
| Airline | Best month | Worst month |
|---|---|---|
| Delta Air Lines | November (93.3%) | July (68.7%) |
| Alaska Airlines | October (84.6%) | January (65.4%) |
Month by month, last 12 months
Share of scheduled flights on time U.S. average 75.6%
Show as table
| Period | On time | Flights |
|---|---|---|
| Sep 2025 | 89.0% | 283 |
| Oct 2025 | 80.7% | 295 |
| Nov 2025 | 84.0% | 257 |
| Dec 2025 | 60.2% | 269 |
| Jan 2026 | 72.4% | 214 |
| Feb 2026 | 74.6% | 193 |
| Mar 2026 | 67.7% | 232 |
| Apr 2026 | 87.7% | 252 |
| May 2026 | 76.7% | 296 |
| Jun 2026 | 76.2% | 324 |
| Jul 2026 | 68.1% | 348 |
| Aug 2026 | 74.6% | 334 |
Best and worst departure times
Share of scheduled flights on time
Show as table
| Period | On time | Flights |
|---|---|---|
| Departing 6 am to 7 am | Insufficient sample | 31 |
| Departing 7 am to 8 am | 79.7% | 655 |
| Departing 8 am to 9 am | 83.1% | 77 |
| Departing 9 am to 10 am | 81.0% | 526 |
| Departing 10 am to 11 am | Insufficient sample | 7 |
| Departing 11 am to noon | 79.9% | 264 |
| Departing noon to 1 pm | 78.6% | 187 |
| Departing 1 pm to 2 pm | 85.1% | 134 |
| Departing 2 pm to 3 pm | 74.5% | 94 |
| Departing 3 pm to 4 pm | 80.6% | 72 |
| Departing 4 pm to 5 pm | 69.1% | 385 |
| Departing 5 pm to 6 pm | Insufficient sample | 39 |
| Departing 6 pm to 7 pm | 68.0% | 175 |
| Departing 7 pm to 8 pm | 62.9% | 299 |
| Departing 8 pm to 9 pm | 67.2% | 67 |
| Departing 9 pm to 10 pm | 76.5% | 285 |
Sources & data dates
- Source
- U.S. DOT Bureau of Transportation Statistics, Reporting Carrier On-Time Performance (1987-present)
- Period
- September 2025 to August 2026 (12 months); month-of-year patterns September 2023 to August 2026
- Data through
- August 2026
- Processed
- 2026-11-03
- Scope
- Nonstop scheduled flights from Atlanta, GA (ATL) to Seattle, WA (SEA), one direction. Airlines that report to the DOT only.
- Method
- Rates use all scheduled flights as the denominator; cancelled and diverted flights count as not on time. Figures based on fewer than 50 scheduled flights are suppressed. Full methodology.