Carrier route record

ASRDU→SEA

Alaska Airlines · Raleigh to Seattle

Flights: 554
Period: September 2025 to August 2026
Share of route: 60%
Carriers: 2

Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Alaska Airlines.

Alaska on RDU to SEA sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.3%. The late ones land roughly 50 minutes behind schedule. That rests on 554 flights, with a median arrival 3 minutes early.

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

On time

74.9%

Arrivals under 15 minutes late, of 546 completed flights

Avg delay

52 min

Across delayed arrivals only, not all flights

Cancelled

1.08%

National rate is 1.89%

Whole route

78.0%

Every carrier on RDU to SEA, 918 flights

These figures cover 554 flights between September 2025 and August 2026. The median arrival is 3 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 RDU to SEA

Alaska flew 554 of the 918 flights on RDU to SEA, most of the route. Its 74.9% on time is 3 points worse than the route as a whole, which runs 78.0%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Delta at 82.8% to Alaska at 74.9%. 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 RDU to SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Linesthin sample	364	82.8%	49 min	1.37%	B
Alaska Airlines (this page)	554	74.9%	52 min	1.08%	C

Flight by flight

Alaska flight numbers on RDU to SEA

AS 57217:3472.0% · 321 flights

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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 554 flights.

5am–8am224 flights79.4%
8am–11am—
11am–2pm—
2pm–5pm—
5pm–8pm330 flights71.8%
8pm–5am—

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

The early departures do better, though not dramatically: 79.4% on time for the 5am–8am window against 71.8% for 5pm–8pm. Worth taking if the schedule allows, not worth an extra connection. The 5pm–8pm window is the busiest, with 330 flights scheduled in it.

Across the year

Alaska on RDU to SEA through the year

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

December is the weak month at 40.5% on time, against 91.1% 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. May was the busiest month here, with 62 flights.

Across the week, Wednesday is the strongest day at 79.7% on time and Monday the weakest at 70.6%, a spread of 9 points.

Arrival by arrival

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

Alaska on RDU to SEA often beats the schedule: 156 of 546 completed flights, 29%, arrived 15 minutes or more early. The 137 late arrivals split 65 under half an hour, 42 between 30 and 60 minutes, and 30 an hour or more.

15+ min early156 flights28.6%
Within 15 min253 flights46.3%
15–29 min late65 flights11.9%
30–59 min late42 flights7.7%
1–2 hours late20 flights3.7%
2+ hours late10 flights1.8%

Scale runs 0% to 100%.

Share of 546 completed flights by arrival against schedule.

A late pushback is often recovered here: of 129 departures that left 15 minutes late or more, 46 still arrived on time. In the other direction, 54 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 RDU to SEA

The latest arrival of the period was on 21 June 2026, 8 hours 35 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on four of the five worst days.

The latest arrivals of Alaska on RDU to SEA in the period
Date	Arrived late by	Largest filed cause
21 June 2026	8 hours 35 minutes	Late-arriving aircraft
27 August 2026	5 hours 20 minutes	Carrier
20 July 2026	4 hours 48 minutes	Late-arriving aircraft
10 December 2025	3 hours 36 minutes	Late-arriving aircraft
13 March 2026	3 hours 13 minutes	Late-arriving aircraft

Delay causes

Why Alaska runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 7,072 reported delay minutes.

Late-arriving aircraft
37%
Carrier
31%
National Airspace System
29%
Security
1%
Extreme weather
1%

37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 7,072 reported delay minutes here, that single category outweighs weather by 29 to one. The split is drawn from 7,072 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 79.4% on time here.

Cancellations sit at 1.08% against a national 1.89%, which is ordinary. Diversions add another 0.36%.

Connections and stage length

What a delay here costs

5.5% 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 50 minutes, which a normal layover absorbs.

At 2,354 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 84.5% on time across 554 flights, 10 points above 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 10 points of difference.

One caution: this is a thin sample. 554 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 RDU to SEA

Put together: treat all of this as provisional. 554 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 74.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 546 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