Carrier route record
ASSEA→RDU
Alaska Airlines · Seattle to Raleigh
- Flights
- 555
- Period
- July 2025 to June 2026
- Share of route
- 60%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Alaska Airlines.
Alaska on SEA to RDU lands a B+, 2 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 40 minutes on average. That is a workable record, not a spotless one. That rests on 555 flights, with a median arrival 4 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Alaska on SEA to RDU from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
79.8%
Arrivals under 15 minutes late, of 550 completed flights
Avg delay
40 min
Across delayed arrivals only, not all flights
Cancelled
0.90%
National rate is 1.81%
Whole route
78.6%
Every carrier on SEA to RDU, 919 flights
These figures cover 555 flights between July 2025 and June 2026. The median arrival is 4 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.
Carrier by carrier
Alaska against every carrier on SEA to RDU
Alaska flew 555 of the 919 flights on SEA to RDU, most of the route. Its 79.8% on time is about level with the route as a whole at 78.6%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Alaska at 79.8% to Delta at 76.8%. 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) | 555 | 79.8% | 40 min | 0.90% | B+ |
| Delta Air Linesthin sample | 364 | 76.8% | 49 min | 1.37% | B |
Flight by flight
Alaska flight numbers on SEA to RDU
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 555 flights.
- 5am–8am—
- 8am–11am364 flights82.9%
- 11am–2pm—
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am191 flights73.9%
Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 82.9% of the time, against 73.9% for the overnight window. That is 9 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 364 flights scheduled in it.
Across the year
Alaska on SEA to RDU through the year
July is the worst month at 57.4% on time, 37 points below October, the best at 93.9%. 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. May was the busiest month here, with 62 flights.
Across the week, Wednesday is the strongest day at 85.7% on time and Monday the weakest at 73.8%. 12 points is a smaller lever than departure hour, but it is free.
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 4,385 reported delay minutes.
- 36%Carrier
- 32%Late-arriving aircraft
- 29%National Airspace System
- 2%Extreme weather
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 1,594 of the 4,385 delay minutes reported here. The split is drawn from 4,385 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 82.9% on time here.
Cancellations sit at 0.90% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
Badly late arrivals are rare here: only 2.7% land an hour or more behind schedule, against 8.1% 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 2,354 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 71.1% on time across 555 flights, 9 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 9 points of difference.
One caution: this is a thin sample. 555 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 RDU
Put together: treat all of this as provisional. 555 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 79.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 550 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to RDU, every carrier
- Alaska on RDU to SEA, the return leg
- Delta Air Lines on SEA to RDU76.8%
- Alaska Airlines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Raleigh-Durham International (RDU) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.