Route reliability record
SEA→PDX
Seattle to Portland
- Flights
- 4,748
- Period
- June 2025 to May 2026
- Distance
- 129 mi
- Carriers
- 3
This route lands a B+, 5 points better than the national rate of 77.4%. About one flight in six arrive 15 minutes late or worse, and those flights are late by about 50 minutes on average. That is a workable record, not a spotless one. That rests on 4,748 flights, of which SkyWest Airlines flew 3,305 at 85.7% on time.
Set against the rest of the country, this route's record is 5 points better than the US average of 77.4%. That gap is worth roughly 50 fewer late arrivals for every thousand flights.
Key figures
On time
82.4%
Arrivals under 15 minutes late, of 4,715 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.70%
National rate is 1.80%
Best carrier
SkyWest
85.7% on time across 3,305 flights
These figures cover 4,748 flights between June 2025 and May 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.
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 85.7% of the time; Alaska Airlines manages 74.3%. Sample sizes sit next to every figure, because a two-point gap across 1,102 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 3,305 | 85.7% | 54 min | 0.51% | A+ |
| Delta Air Linesthin sample | 341 | 75.4% | 62 min | 0.00% | B+ |
| Alaska Airlines | 1,102 | 74.3% | 42 min | 1.45% | C |
SkyWest leads Alaska by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am587 flights93.8%
- 8am–11am553 flights88.6%
- 11am–2pm990 flights80.8%
- 2pm–5pm700 flights79.3%
- 5pm–8pm702 flights80.7%
- 8pm–5am1,216 flights77.9%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.8% of the time, against 77.9% 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.
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.
June is the worst month at 72.0% 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.
Across the week, Wednesday is the strongest day at 84.7% on time and Thursday the weakest at 77.6%. 7 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Carrier accounts for 49% of the 42,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 49%Carrier
- 26%Late-arriving aircraft
- 12%National Airspace System
- 12%Extreme weather
- 0%Security
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 1.9 times the usual weather exposure.
The largest share of delay minutes, 49%, 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 21,000 of the 42,000 delay minutes reported here.
Cancellations are rare at 0.70%, below the national 1.80% 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 4.1% land an hour or more behind schedule, against 8.2% 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 84.1% on time across 4,937 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.
The sample behind these figures is 4,748 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.
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 June 72.0%, a swing of 19 points. If the dates move at all, move them out of June before you think about anything else.
Common questions
SEA to PDX questions
How often is SEA to PDX delayed?
About one flight in six arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 17.6% of the 4,748 flights in this analysis, against 22.6% nationally. Delayed flights are late by about 50 minutes on average.
Which airline is most reliable on SEA to PDX?
SkyWest Airlines leads at 85.7% on time across 3,305 flights. Alaska Airlines is at the other end on 74.3%, a gap of 11 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 93.8% on time. The 8pm–5am window is the weakest at 77.9%, 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 June delays on SEA to PDX?
June is the weakest month at 72.0% 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-time record85.7%
- Delta Air Lines on-time record75.4%
- Alaska Airlines on-time record74.3%
- The best time of day to fly, according to 7.05 million flight records
- Do budget airlines really get delayed more? The numbers
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.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.