Carrier route record
ASSEA→DCA
Alaska Airlines · Seattle to Washington
- Flights
- 728
- Period
- September 2025 to August 2026
- Share of route
- 67%
- 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 DCA lands a B+, level with the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 55 minutes on average. That rests on 728 flights, with a median arrival 14 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate Alaska on SEA to DCA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.0%
Arrivals under 15 minutes late, of 713 completed flights
Avg delay
54 min
Across delayed arrivals only, not all flights
Cancelled
0.69%
National rate is 1.89%
Whole route
82.6%
Every carrier on SEA to DCA, 1,092 flights
These figures cover 728 flights between September 2025 and August 2026. The median arrival is 14 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 DCA
Alaska flew 728 of the 1,092 flights on SEA to DCA, most of the route. Its 78.0% on time is 5 points worse than the route as a whole, which runs 82.6%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Delta at 91.8% to Alaska at 78.0%. 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 |
|---|---|---|---|---|---|
| Delta Air Linesthin sample | 364 | 91.8% | 119 min | 2.75% | A |
| Alaska Airlines (this page) | 728 | 78.0% | 54 min | 0.69% | B+ |
Flight by flight
Alaska flight numbers on SEA to DCA
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Departure window
When Alaska runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 17 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am364 flights85.2%
- 11am–2pm186 flights68.3%
- 2pm–5pm178 flights73.2%
- 5pm–8pm—
- 8pm–5am—
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 68.3% on time against 85.2% for 8am–11am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8am–11am window is the busiest, with 364 flights scheduled in it.
Across the year
Alaska on SEA to DCA through the year
April is the best month on the calendar at 90.0% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. January was the busiest month here, with 62 flights.
Across the week, Saturday is the strongest day at 88.9% on time and Monday the weakest at 71.8%, a spread of 17 points.
Arrival by arrival
How late Alaska on SEA to DCA runs when it is late
Alaska on SEA to DCA often beats the schedule: 350 of 713 completed flights, 49%, arrived 15 minutes or more early. The 157 late arrivals split 50 under half an hour, 60 between 30 and 60 minutes, and 47 an hour or more.
- 15+ min early350 flights49.1%
- Within 15 min206 flights28.9%
- 15–29 min late50 flights7.0%
- 30–59 min late60 flights8.4%
- 1–2 hours late33 flights4.6%
- 2+ hours late14 flights2.0%
Scale runs 0% to 100%.
Share of 713 completed flights by arrival against schedule.
41 of 176 late departures made up the time and arrived on time, 23% of them. 22 flights left on time and still arrived late.
The worst days
Worst days for Alaska on SEA to DCA
The latest arrival of the period was on 29 January 2026, 3 hours 47 minutes behind schedule; most of its delay minutes were filed as extreme weather. Four of the five worst days fell in January 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 29 January 2026 | 3 hours 47 minutes | Extreme weather |
| 26 January 2026 | 3 hours 25 minutes | Extreme weather |
| 30 January 2026 | 2 hours 56 minutes | Extreme weather |
| 27 January 2026 | 2 hours 50 minutes | National Airspace System |
| 16 March 2026 | 2 hours 38 minutes | National Airspace System |
Delay causes
Why Alaska runs late on this route
National Airspace System accounts for 55% of the 8,422 delay minutes carriers reported here, and the remaining four split what is left.
- 55%National Airspace System
- 20%Carrier
- 15%Late-arriving aircraft
- 11%Extreme weather
55% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 4,608 minutes out of 8,422, against a national NAS share of 21%. The split is drawn from 8,422 reported delay minutes.
Cancellations are rare at 0.69%, 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
6.6% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 55 minutes, which a normal layover absorbs.
At 2,329 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 runs 76.4% on time across 728 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 728 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 DCA
Put together: treat all of this as provisional. 728 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 78.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 713 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to DCA, every carrier
- Alaska on DCA to SEA, the return leg
- Delta Air Lines on SEA to DCA91.8%
- Alaska Airlines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Ronald Reagan Washington National (DCA) delay statistics
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
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.