About 1 in 6 AS 378 flights from Seattle arrived 15+ minutes late, diverted or cancelled over the past year (18%); 0.6% were cancelled. The typical flight landed 9 minutes early.
AS 378: SEA → BWI
Scheduled to leave Seattle at 9:03 a.m. local time. Over the past year it arrived on time 82% of the time (337 flights), in line with other AS flights on the route at that hour (85%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 49 | 76% |
| Tuesday | 48 | 81% |
| Wednesday | 48 | 88% |
| Thursday | 48 | 73% |
| Friday | 48 | 88% |
| Saturday | 48 | 90% |
| Sunday | 48 | 83% |
Why it was late
All flights SEA → BWI · Connecting off AS 378? Check the risk
Questions
How often is AS 378 from SEA to BWI late?
Alaska Airlines 378 from Seattle, WA to Baltimore, MD arrived 15 or more minutes late, was diverted or was cancelled on 18% of 337 scheduled flights between September 2025 and August 2026. 0.6% were cancelled.
Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check Alaska Airlines for today's flight. Method.