Route reliability record
PDX→LAX
Portland to Los Angeles
- Flights
- 4,447
- Period
- June 2025 to May 2026
- Distance
- 833 mi
- Carriers
- 4
This route earns a A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.4%. When something does go wrong the average delay runs a little over an hour. That rests on 4,447 flights, of which Delta Air Lines flew 1,690 at 90.9% on time.
Delta Air Lines is the most reliable of the three carriers covered here at 90.9% on time across 1,690 flights.
Key figures
On time
86.8%
Arrivals under 15 minutes late, of 4,402 completed flights
Avg delay
77 min
Across delayed arrivals only, not all flights
Cancelled
0.99%
National rate is 1.80%
Best carrier
Delta
90.9% on time across 1,690 flights
These figures cover 4,447 flights between June 2025 and May 2026. The median arrival is 10 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 PDX to LAX
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 90.9% of the time; SkyWest Airlines manages 79.8%. Sample sizes sit next to every figure, because a two-point gap across 598 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,690 | 90.9% | 103 min | 0.89% | A+ |
| Alaska Airlines | 1,940 | 85.8% | 48 min | 1.03% | A |
| Frontier Airlinesthin sample | 219 | 82.1% | 65 min | 3.20% | B− |
| SkyWest Airlines | 598 | 79.8% | 115 min | 0.33% | B+ |
Delta leads SkyWest 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 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 4,447 flights.
- 5am–8am980 flights89.3%
- 8am–11am677 flights86.9%
- 11am–2pm766 flights89.5%
- 2pm–5pm549 flights83.2%
- 5pm–8pm900 flights85.5%
- 8pm–5am575 flights84.2%
Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 89.5% on time, ahead of 2pm–5pm at 83.2%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation.
Across the year
When delays peak on this route
This route's year swings by 12 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.
December is the weak month at 80.2% on time, against 92.2% 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.
Across the week, Wednesday is the strongest day at 89.4% on time and Sunday the weakest at 84.6%. 5 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 50% of the 45,000 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.
- 50%Carrier
- 41%Late-arriving aircraft
- 8%National Airspace System
- 1%Extreme weather
- 0%Security
41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 45,000 reported delay minutes here, that single category outweighs weather by 41 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit.
The largest share of delay minutes, 50%, 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 23,000 of the 45,000 delay minutes reported here.
Cancellations sit at 0.99% against a national 1.80%, which is ordinary. Diversions add another 0.02%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.7% 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.
The 833 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 86.0% on time across 4,450 flights, within about a point 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 4,447 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. September runs 92.2% on time and December 80.2%, a swing of 12 points. If the dates move at all, move them out of December before you think about anything else.
Common questions
PDX to LAX questions
How often is PDX to LAX delayed?
About one flight in eight arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 13.2% of the 4,447 flights in this analysis, against 22.6% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on PDX to LAX?
Delta Air Lines leads at 90.9% on time across 1,690 flights. SkyWest Airlines is at the other end on 79.8%, 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 PDX to LAX?
The 11am–2pm departure window is the strongest at 89.5% on time. The 2pm–5pm window is the weakest at 83.2%, 6 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 December delays on PDX to LAX?
December is the weakest month at 80.2% on time, compared with 92.2% in September. Across the year that is 12 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
- LAX to PDX — the return legseparate record
- Portland International (PDX) delay statistics
- Los Angeles International (LAX) delay statistics
- Delta Air Lines on-time record90.9%
- Alaska Airlines on-time record85.8%
- Frontier Airlines on-time record82.1%
- Why the first flight of the morning is statistically safest
- Do budget airlines really get delayed more? The numbers
Direction matters. PDX to LAX and LAX to PDX 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.