Carrier route record
ASSEA→BWI
Alaska Airlines · Seattle to Baltimore
- Flights
- 599
- Period
- September 2025 to August 2026
- Share of route
- 83%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Alaska Airlines.
Alaska on SEA to BWI earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 40 minutes. That rests on 599 flights, with a median arrival 10 minutes early.
Set against the rest of the country, Alaska's SEA to BWI record is 8 points better than the US average of 77.3%. That gap is worth roughly 75 fewer late arrivals for every thousand flights.
Key figures
On time
84.8%
Arrivals under 15 minutes late, of 591 completed flights
Avg delay
39 min
Across delayed arrivals only, not all flights
Cancelled
0.67%
National rate is 1.89%
Whole route
80.7%
Every carrier on SEA to BWI, 719 flights
These figures cover 599 flights between September 2025 and August 2026. The median arrival is 10 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
Alaska against every carrier on SEA to BWI
Alaska flew 599 of the 719 flights on SEA to BWI, most of the route. Its 84.8% on time is 4 points better than the route as a whole, which runs 80.7%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Alaska at 84.8% to Southwest at 60.5%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlines (this page) | 599 | 84.8% | 39 min | 0.67% | B+ |
| Southwest Airlinesthin sample | 120 | 60.5% | 40 min | 0.83% | D+ |
Flight by flight
Alaska flight numbers on SEA to BWI
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Alaska runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 599 flights.
- 5am–8am—
- 8am–11am365 flights84.1%
- 11am–2pm—
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am234 flights85.8%
Scale runs 75% to 90%. Rows with fewer than 30 flights show a dash.
The overnight block holds up unusually well at 85.8% on time across 234 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8am–11am window is the busiest, with 365 flights scheduled in it.
Across the year
Alaska on SEA to BWI through the year
August is the worst month at 75.0% on time, 20 points below April, the best at 94.7%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. August was the busiest month here, with 62 flights.
Across the week, Saturday is the strongest day at 92.0% on time and Thursday the weakest at 77.6%, a spread of 14 points.
Arrival by arrival
How late Alaska on SEA to BWI runs when it is late
Alaska on SEA to BWI often beats the schedule: 242 of 591 completed flights, 41%, arrived 15 minutes or more early. Most of the lateness is short. 50 of the 90 late arrivals were under half an hour behind, and 11 reached an hour or more.
- 15+ min early242 flights40.9%
- Within 15 min259 flights43.8%
- 15–29 min late50 flights8.5%
- 30–59 min late29 flights4.9%
- 1–2 hours late6 flights1.0%
- 2+ hours late5 flights0.8%
Scale runs 0% to 100%.
Share of 591 completed flights by arrival against schedule.
A late pushback is often recovered here: of 127 departures that left 15 minutes late or more, 56 still arrived on time. 19 flights left on time and still arrived late.
The worst days
Worst days for Alaska on SEA to BWI
The latest arrival of the period was on 13 March 2026, 3 hours 40 minutes behind schedule; most of its delay minutes were filed as extreme weather. On four of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 13 March 2026 | 3 hours 40 minutes | Extreme weather |
| 12 November 2025 | 3 hours 24 minutes | Carrier |
| 8 January 2026 | 3 hours 2 minutes | Carrier |
| 2 April 2026 | 2 hours 22 minutes | Carrier |
| 9 September 2025 | 2 hours 1 minute | Carrier |
Delay causes
Why Alaska runs late on this route
Carrier accounts for 49% of the 3,549 delay minutes carriers reported here, and the remaining four split what is left.
- 49%Carrier
- 28%Late-arriving aircraft
- 18%National Airspace System
- 6%Extreme weather
The largest share of delay minutes, 49%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,723 of the 3,549 delay minutes reported here. The split is drawn from 3,549 reported delay minutes.
Cancellations are rare at 0.67%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
Badly late arrivals are rare here: only 1.9% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 2,335 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 68.2% on time across 599 flights, 17 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 17 points of difference.
One caution: this is a thin sample. 599 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Alaska on SEA to BWI
Put together: treat all of this as provisional. 599 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 84.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 591 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to BWI, every carrier
- Alaska on BWI to SEA, the return leg
- Southwest Airlines on SEA to BWI60.5%
- Alaska Airlines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- Worst months to fly in the US, ranked by the data
- The best day of the week to fly, and why it is the second lever
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.