Carrier route record

ASDCA→SEA

Alaska Airlines · Washington to Seattle

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 DCA to SEA lands a B+, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about 50 minutes on average. That rests on 728 flights, with a median arrival 6 minutes early.

The US average over the same twelve months is 77.3%, so there is little to separate Alaska on DCA to SEA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

76.4%

Arrivals under 15 minutes late, of 717 completed flights

Avg delay

50 min

Across delayed arrivals only, not all flights

Cancelled

0.69%

National rate is 1.89%

Whole route

73.4%

Every carrier on DCA to SEA, 1,092 flights

These figures cover 728 flights between September 2025 and August 2026. The median arrival is 6 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 DCA to SEA

Alaska flew 728 of the 1,092 flights on DCA to SEA, most of the route. Its 76.4% on time is 3 points better than the route as a whole, which runs 73.4%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Alaska at 76.4% to Delta at 67.2%. 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.

On-time performance by carrier on DCA to SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Alaska Airlines (this page)	728	76.4%	50 min	0.69%	B+
Delta Air Linesthin sample	364	67.2%	88 min	2.75%	C

Flight by flight

Alaska flight numbers on DCA to SEA

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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 728 flights.

5am–8am—
8am–11am365 flights79.9%
11am–2pm—
2pm–5pm—
5pm–8pm363 flights72.9%
8pm–5am—

Scale runs 65% to 85%. Rows with fewer than 30 flights show a dash.

The early departures do better, though not dramatically: 79.9% on time for the 8am–11am window against 72.9% for 5pm–8pm. Worth taking if the schedule allows, not worth an extra connection. The 8am–11am window is the busiest, with 365 flights scheduled in it.

Across the year

Alaska on DCA to SEA through the year

Darker means more delays. Figures are on-time percentages.September best, December worst

December is the weak month at 46.8% on time, against 93.3% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. January was the busiest month here, with 62 flights.

Across the week, Saturday is the strongest day at 87.3% on time and Wednesday the weakest at 70.2%, a spread of 17 points.

Arrival by arrival

How late Alaska on DCA to SEA runs when it is late

Alaska on DCA to SEA often beats the schedule: 245 of 717 completed flights, 34%, arrived 15 minutes or more early. The 169 late arrivals split 72 under half an hour, 54 between 30 and 60 minutes, and 43 an hour or more.

15+ min early245 flights34.2%
Within 15 min303 flights42.3%
15–29 min late72 flights10.0%
30–59 min late54 flights7.5%
1–2 hours late31 flights4.3%
2+ hours late12 flights1.7%

Scale runs 0% to 100%.

Share of 717 completed flights by arrival against schedule.

30 of 120 late departures made up the time and arrived on time, 25% of them. In the other direction, 79 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SEA.

The worst days

Worst days for Alaska on DCA to SEA

The latest arrival of the period was on 11 June 2026, 4 hours 35 minutes behind schedule; most of its delay minutes were filed as extreme weather. The five worst days are spread across June, July, April and March, with no single month standing out.

The latest arrivals of Alaska on DCA to SEA in the period
Date	Arrived late by	Largest filed cause
11 June 2026	4 hours 35 minutes	Extreme weather
18 July 2026	4 hours 32 minutes	Late-arriving aircraft
5 April 2026	4 hours 16 minutes	Carrier
14 March 2026	3 hours 58 minutes	Carrier
13 March 2026	3 hours 21 minutes	National Airspace System

Delay causes

Why Alaska runs late on this route

National Airspace System accounts for 46% of the 8,506 delay minutes carriers reported here, and the remaining four split what is left.

National Airspace System
46%
Late-arriving aircraft
21%
Carrier
20%
Extreme weather
12%

Extreme weather accounts for 12% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.0 times the usual weather exposure. The split is drawn from 8,506 reported delay minutes.

46% 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 3,922 minutes out of 8,506, against a national NAS share of 21%.

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

6.0% 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 about 50 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 78.0% 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 DCA to SEA

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 76.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 717 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures