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DelayAtlas

Carrier performance at one airport

WNPDX

Southwest Airlines at Portland International

Departures
8,633
Period
June 2025 to May 2026
Routes
12
Rank here
#6 of 9
B+GRADE

Southwest Airlines at Portland lands a B+, level with the national rate of 77.4%. Roughly one flight in four arrive 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That is a workable record, not a spotless one. That rests on 8,633 flights, of which Delta Air Lines flew 7,318 at 89.4% on time.

Measured against the airport rather than the country, Southwest Airlines runs 5 points behind the 82.4% weighted average across all carriers at PDX. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.

Key figures

On time

77.1%

8,585 completed departures

Avg delay

48 min

Across delayed flights only

Cancelled

0.32%

At PDX, this carrier only

Rank here

#6

Of 9 carriers clearing the floor at PDX

These figures cover 8,633 flights between June 2025 and May 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

Against the competition

Every carrier at PDX, ranked

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 89.4% of the time; Hawaiian Airlines manages 57.7%. Sample sizes sit next to every figure, because a two-point gap across 540 flights means less than a ten-point one.

On-time performance of all carriers departing PDX
AirlineFlightsOn timeAvg delayCancelledGrade
Delta Air Lines7,31889.4%77 min0.98%A+
SkyWest Airlines10,45284.7%63 min0.57%B+
Alaska Airlines22,84082.8%47 min0.74%B+
United Airlines6,52182.3%65 min0.67%B+
American Airlines4,38679.7%98 min1.92%B
Southwest Airlines (this page)8,63377.1%48 min0.32%B+
Frontier Airlines1,00876.1%74 min1.79%B
Allegiant Air43672.1%119 min0.00%C+
Hawaiian Airlines54057.7%74 min0.93%D+

The spread between Delta and Hawaiian is 32 points, wide enough that it should decide the booking. On a hundred trips that is 32 more arrivals inside the on-time window.

Route by route

Where Southwest Airlines flies from PDX

Southwest Airlines operates 12 routes out of PDX with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.

Southwest Airlines routes from PDX
RouteFlightsOn timeAvg delayCancelledGrade
PDX to DEN · Denver1,57372.0%48 min0.25%C+
PDX to PHX · Phoenix1,27876.4%48 min0.23%B+
PDX to OAK · Oakland1,20476.0%51 min0.75%B+
PDX to SMF · Sacramento1,20279.4%51 min0.25%B+
PDX to LAS · Las Vegas1,15078.5%45 min0.17%B+
PDX to SJC · San Jose99977.0%52 min0.20%B+
PDX to MDW · Chicago68688.8%40 min0.73%A+
PDX to DAL · Dallasthin sample22660.0%37 min0.00%D+
PDX to BWI · Baltimorethin sample11979.8%40 min0.00%B+
PDX to SAN · San Diegothin sample11584.3%31 min0.00%B+
PDX to STL · St. Louisthin sample3476.5%28 min0.00%B+
PDX to MCI · Kansas Citythin sample3390.9%21 min0.00%A+

Departure window

Best time of day for this operation

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 34 points, against 32 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am2,484 flights94.8%
  • 8am–11am1,484 flights85.3%
  • 11am–2pm1,329 flights73.2%
  • 2pm–5pm1,339 flights61.7%
  • 5pm–8pm1,163 flights60.8%
  • 8pm–5am834 flights63.0%

Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 60.8% on time, against 94.8% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in.

Across the year

Seasonal pattern

On-time rate by calendar month90J82F78M78A75M72J67J79A78S78O81N74D
Darker means more delays. Figures are on-time percentages.January best, July worst

July is the worst month at 67.3% on time, 22 points below January, the best at 89.5%. 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.

Delay causes

What holds this operation up

  • Late-arriving aircraft
    58%
  • Carrier
    26%
  • National Airspace System
    15%
  • Extreme weather
    1%
  • Security
    0%

58% 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 94,000 reported delay minutes here, that single category outweighs weather by 58 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.

Cancellations are rare at 0.32%, 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.

Badly late arrivals are rare here: only 4.9% 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 sample behind these figures is 8,633 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.

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 89.5% on time and July 67.3%, a swing of 22 points. If the dates move at all, move them out of July before you think about anything else.

Common questions

Southwest Airlines at PDX

How often is Southwest Airlines at PDX delayed?

Roughly one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.9% of the 8,633 flights in this analysis, against 22.6% nationally. Delayed flights are late by roughly 50 minutes on average.

Which airline is most reliable on Southwest Airlines at PDX?

Delta Air Lines leads at 89.4% on time across 7,318 flights. Hawaiian Airlines is at the other end on 57.7%, a gap of 32 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 Southwest Airlines at PDX?

The 5am–8am departure window is the strongest at 94.8% on time. The 5pm–8pm window is the weakest at 60.8%, 34 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 July delays on Southwest Airlines at PDX?

July is the weakest month at 67.3% on time, compared with 89.5% in January. Across the year that is 22 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

Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.