Baltimore (BWI) to Seattle (SEA): On-Time Performance
Data through May 2026
Baltimore (BWI) to Seattle (SEA) effectively runs on two schedules. In October 2025, 89% of arrivals were on time; in December 2025 that fell to 32% — a 57-point seasonal swing. Across the full period the route averages 67% on-time against a national 78%. Morning departures also hold up better than evening ones (77% vs 60%), which matters most in the rough months.
- On-time
- 67%
- arrived <15 min late
- Avg delay
- 19 min
- completed flights
- Cancelled
- 0.7%
- Flights/day
- 2.0
- last 12 months
- Duration
- 5h 51m
- scheduled
- Distance
- 2,335 mi
Best airline from BWI to SEA
2 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| Southwest Airlinesmost reliable | 70% | 29 min | 0.0% | 128 |
| Alaska Airlines | 67% | 18 min | 0.8% | 1,176 |
Monthly on-time trend
Best time to fly from BWI to SEA
Aim for departures around 7 a.m. (76% on-time); avoid 2 p.m. departures (45%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 69% | 20 min |
| Tuesdaybest | 72% | 15 min |
| Wednesday | 67% | 21 min |
| Thursday | 65% | 19 min |
| Friday | 60% | 20 min |
| Saturday | 68% | 17 min |
| Sunday | 69% | 18 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft34%
- Airline operations22%
- National airspace system33%
- Weather10%
- Security1%
Frequently asked questions
- How often are flights from BWI to SEA delayed?
- 33% of BWI–SEA flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 19 minutes.
- Which airline is most reliable from BWI to SEA?
- Southwest Airlines has the best on-time record on this route at 70%, based on 128 flights. 2 airlines flew BWI–SEA frequently enough to compare in this period.
- What is the best time of day to fly from BWI to SEA?
- Departures around 7 a.m. have the best record (76% on-time), while departures around 2 p.m. have the worst (45%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from BWI to SEA?
- The scheduled BWI–SEA flight time averages 5h 51m over 2,335 miles. Actual arrival times vary — flights on this route land 15+ minutes late 33% of the time.
- How often are BWI to SEA flights cancelled?
- 0.7% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
- What is the worst month to fly from BWI to SEA?
- December 2025 was the roughest month in this dataset, with only 32% of arrivals on time. The best was October 2025 at 89%. If your dates are flexible, that 57-point gap is worth planning around.
Explore related pages
More routes from BWI
Based on 1,304 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.