Route reliability record
SEA→PDX
Seattle to Portland
- Flights
- 4,826
- Period
- September 2025 to August 2026
- Distance
- 129 mi
- Carriers
- 3
This route lands a B+, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about 50 minutes on average. That rests on 4,826 SEA to PDX flights, of which SkyWest Airlines flew 3,375 at 84.6% on time.
Best time to fly SEA to PDX: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 92.8% of the time and Saturday flights 84.9%, against 82.2% for the route overall.
Set against the rest of the country, this route's record is 5 points better than the US average of 77.3%. That gap is worth roughly 49 fewer late arrivals for every thousand flights.
Key figures
On time
82.2%
Arrivals under 15 minutes late, of 4,791 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
0.73%
National rate is 1.89%
Best carrier
SkyWest
84.6% on time across 3,375 flights
These figures cover 4,826 flights between September 2025 and August 2026. The median arrival is 5 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
Which airline is most reliable on SEA to PDX
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 84.6% of the time; Alaska Airlines manages 76.7%. Sample sizes sit next to every figure, because a two-point gap across 1,202 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 3,375 | 84.6% | 52 min | 0.56% | B+ |
| Alaska Airlines | 1,202 | 76.7% | 42 min | 1.33% | B |
| Delta Air Linesthin sample | 249 | 76.3% | 65 min | 0.00% | B+ |
SkyWest leads Alaska by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on SEA to PDX
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Seattle to Portland
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SEA → PDXSeattle to Portland | SkyWest Airlines | 84.1% | 84.6% | 0.56% | 5am–8am, Sun | OO 3953 07:25 |
| 2. SEA → PDXSeattle to Portland | Alaska Airlines | 75.7% | 76.7% | 1.33% | 5am–8am, Tue | AS 498 23:15 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 16 points, against 8 points between the best and worst carrier.
- 5am–8am519 flights92.8%
- 8am–11am809 flights86.4%
- 11am–2pm900 flights82.9%
- 2pm–5pm673 flights78.8%
- 5pm–8pm656 flights82.7%
- 8pm–5am1,269 flights76.4%
Scale runs 70% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.8% of the time, against 76.4% for the overnight window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 1,269 flights scheduled in it.
Explore
Filter SEA to PDX by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SEA to PDX, the best departure window is 5am–8am at 92.8% on time and the worst is 8pm–5am at 76.4%, a wide gap of 16.4 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am92.8%
- 8–11am86.4%
- 11am–2pm82.9%
- 2–5pm78.8%
- 5–8pm82.7%
- 8pm–5am76.4%
best all US flightsScale 60% to 95%.
Across the year
When delays peak on this route
This route's year swings by 19 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
August is the worst month at 71.7% on time, 19 points below April, the best at 90.6%. 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. September was the busiest month here, with 433 flights.
Across the week, Saturday is the strongest day at 84.9% on time and Thursday the weakest at 77.6%, a spread of 7 points.
Delay causes
Why this route gets delayed
Carrier accounts for 52% of the 42,000 delay minutes carriers reported here, and the remaining four split what is left.
- 52%Carrier
- 21%Late-arriving aircraft
- 14%National Airspace System
- 13%Extreme weather
- 0%Security
Extreme weather accounts for 13% 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 2.2 times the usual weather exposure. The split is drawn from 41,965 reported delay minutes.
The largest share of delay minutes, 52%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 22,000 of the 42,000 delay minutes reported here.
Cancellations are rare at 0.73%, 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 actually costs
Badly late arrivals are rare here: only 4.0% land an hour or more behind schedule, against 8.3% 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 129 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg runs 84.9% on time across 4,927 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 4,826 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in PDX after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 90.6% on time and August 71.7%, a swing of 19 points. If the dates move at all, move them out of August before you think about anything else. 4,791 completed flights over 12 months sit behind that.
Common questions
SEA to PDX questions
How often is SEA to PDX delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 17.8% of the 4,826 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 50 minutes on average.
Which airline is most reliable on SEA to PDX?
SkyWest Airlines leads at 84.6% on time across 3,375 flights. Alaska Airlines is at the other end on 76.7%, a gap of 8 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on SEA to PDX?
The 5am–8am departure window is the strongest at 92.8% on time. The 8pm–5am window is the weakest at 76.4%, 16 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are August delays on SEA to PDX?
August is the weakest month at 71.7% on time, compared with 90.6% in April. Across the year that is 19 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- PDX to SEA — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- Portland International (PDX) delay statistics
- SkyWest Airlines on SEA to PDX84.6%
- Alaska Airlines on SEA to PDX76.7%
- Delta Air Lines on SEA to PDX76.3%
- SEA to LAX, a related route82.0%
- LAX to PDX, a related route86.8%
- SEA to PHX, a related route78.2%
- SkyWest Airlines on-time record84.6%
- Alaska Airlines on-time record76.7%
- Delta Air Lines on-time record76.3%
- 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
Direction matters. SEA to PDX and PDX to SEA are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.