Route profile
SEA→RDU
Flight reliability, delays and best times to fly from Seattle to Raleigh–Durham, 2,354 miles.
Right now
Weather conditions are strongly associated with delays and cancellations.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 86% of comparable major US routes (4,598 compared)
Calculated from 2,787 flights. How this is calculated · What counts as on time
SEA → RDU arrives on time 80.4% of the time; the return trip, RDU → SEA, arrives on time 79.5% of the time.
SEA → RDU spends 29.7 minutes on the ground on a 2,354-mile trip: 22.4 minutes from pushback to wheels-up at SEA and 7.3 minutes from touchdown to gate at RDU.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Unlike most, it barely matters what time you fly this route, a steadier spread than 96% of 4,023 comparable routes.
82.5% on time for 9 AM–12 PM departures, against 76.2% for 9 PM–5 AM, a narrow gap either way.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,023 in the comparison.
What sets this route apart
Where SEA to RDU differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
SEA to RDU is at its best against routes of similar length for flights scheduled at 3 PM: 82.1% arrive on time, 6.8 points ahead of the 75.3% those routes manage at that hour. Against all other routes the gap is 9.4 points.
SEA to RDU struggles most at 9 PM: 74.9% of its flights scheduled then arrive on time, 3.9 points behind the 78.8% on routes of similar length at the same hour.
SEA to RDU holds up on Wednesdays better than routes of similar length do: 84.8% on time to their 80.5%, a 4.3 points lead.
March is kinder to SEA to RDU than to routes of similar length: 86.6% on time against 79.3%, 7.3 points better. Against all other routes the gap is 8.7 points.
Alaska Airlines does better on SEA to RDU than on its routes of similar length: 79.5% on time here, 76.1% there, 3.4 points apart.
SEA to RDU against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 3 PM departures | 82.1% | routes of similar length | 75.3% | +6.8 pts | 873 here, 46,964 there |
| Hour: 9 PM departures | 74.9% | routes of similar length | 78.8% | −3.9 pts | 526 here, 58,351 there |
| Weekday: Wednesday | 84.8% | routes of similar length | 80.5% | +4.3 pts | 388 here, 153,231 there |
| Month: March | 86.6% | routes of similar length | 79.3% | +7.3 pts | 194 here, 86,756 there |
| Airline: Alaska Airlines | 79.5% | routes of similar length | 76.1% | +3.4 pts | 1,644 here, 167,727 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 2,354 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
30 min late
against a median of 5 min early
Percentiles over 2,787 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at RDU after arriving from SEA.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 39% | Likely to miss |
| 45 min | 19% | High risk |
| 60 min | 9.7% | Some risk |
| 90 min | 3.6% | Low risk |
| 120 min | 1.7% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.68% of the time and diverts 0.29% of the time, which a late arrival never shows up in.
Chance of missing is the share of 2,760 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 30 minutes late (90th-percentile gate arrival delay), over 2,787 operations.
Any other layover length: connection checker.
Best time to fly
SEA → RDU flights departing 9 AM–12 PM arrived on time 82.5% of the time, against 76.2% for 9 PM–5 AM departures, a gap of 6.3 percentage points.
By departure window
By departure hour
- 12 AM to 7 AM: too few flights to score
- 8 AM: 81.6% on time from 322 flights
- 9 AM: 81.9% on time from 655 flights
- 10 AM: 84.5% on time from 132 flights
- 11 AM to 2 PM: too few flights to score
- 3 PM: 82.1% on time from 880 flights
- 4 PM to 8 PM: too few flights to score
- 9 PM: 74.9% on time from 532 flights
- 10 PM: 79.7% on time from 194 flights
- 11 PM: too few flights to score
Departure windows with fewer than 120 flights are not scored.
Why SEA → RDU runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for SEA → RDU. Only delays of 15 minutes or more are attributed. What the five causes mean
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Alaska Airlines | 1,663 | 79.5% | 0.72% | -3 min | 2.8% |
| Delta Air Lines | 1,124 | 81.6% | 0.62% | -7 min | 4.9% |
Alaska Airlines flew 59.7% of the 2,787 flights listed.
Delta Air Lines arrived on time 2.1 percentage points more often than Alaska Airlines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Monday the least, a gap of 10.4 percentage points.
By month
- Jan: 85.1%
- Feb: 86.5%
- Mar: 86.6%
- Apr: 80.7%
- May: 77.6%
- Jun: 78.5%
- Jul: 74.5%
- Aug: 74.2%
- Sep: 80.2%
- Oct: 85.1%
- Nov: 86.9%
- Dec: 80.0%
August is historically the weakest month and November the strongest, a spread of 12.7 percentage points.
Reliability over time
July 2023 – July 2026
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 79.9% against 79.6% in the 12 months before — broadly unchanged.
Data and methodology
Calculated by FlyerIntel from 2,787 SEA → RDU flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed