Carrier route record

WNSAN→PDX

Southwest Airlines · San Diego to Portland

Flights: 137
Period: July 2025 to June 2026
Share of route: 8%
Carriers: 3

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.

Southwest on SAN to PDX draws a D+. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is roughly 35 minutes behind schedule. Build slack into anything you connect to. That rests on 137 flights, with a median arrival 6 minutes late.

The national on-time rate over the same period is 77.6%, so Southwest on SAN to PDX runs 14 points behind the country as a whole. Across a thousand flights that is about 141 extra late arrivals.

On time

63.5%

Arrivals under 15 minutes late, of 137 completed flights

Avg delay

36 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.81%

Whole route

84.1%

Every carrier on SAN to PDX, 1,777 flights

These figures cover 137 flights between July 2025 and June 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.

Carrier by carrier

Southwest against every carrier on SAN to PDX

Southwest flew 137 of the 1,777 flights on SAN to PDX, about 8% of it. Its 63.5% on time is 21 points worse than the route as a whole, which runs 84.1%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from SkyWest at 86.7% to Southwest at 63.5%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on SAN to PDX
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlinesthin sample	30	86.7%	69 min	0.00%	A+
Alaska Airlines	1,610	85.9%	54 min	1.18%	A
Southwest Airlines (this page)thin sample	137	63.5%	36 min	0.00%	D+

Departure window

When Southwest runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 27 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am—
8am–11am4 flights—
11am–2pm60 flights76.7%
2pm–5pm68 flights50.0%
5pm–8pm5 flights—
8pm–5am—

Scale runs 40% to 80%. Rows with fewer than 30 flights show a dash.

The best window here is not the first bank but the 11am–2pm slot at 76.7% on time, ahead of 2pm–5pm at 50.0%. 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. The 2pm–5pm window is the busiest, with 68 flights scheduled in it.

Across the year

Southwest on SAN to PDX through the year

Jul–Sep 202510 flights—
Oct–Dec 20258 flights—
Jan–Mar 202628 flights—
Apr–Jun 202691 flights58.2%

Scale runs 50% to 65%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 63.5% on time across 137 flights.

Split by quarter, Southwest on SAN to PDX logged 10 flights in Jul–Sep 2025, 8 flights in Oct–Dec 2025, 28 flights in Jan–Mar 2026 and 91 flights in Apr–Jun 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 63.5% annual figure is the one to use.

Delay causes

Why Southwest runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 53% of the 1,817 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.

Late-arriving aircraft
53%
Carrier
33%
National Airspace System
14%

53% 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 1,817 reported delay minutes here, that single category outweighs weather by 53 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 split is drawn from 1,817 reported delay minutes.

Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

5.1% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 35 minutes, which a normal layover absorbs.

The 933 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 is a different operation and performs like one: it runs 75.9% on time across 137 flights, 12 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 12 points of difference.

One caution: this is a thin sample. 137 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking Southwest on SAN to PDX

Put together: treat all of this as provisional. 137 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 63.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 137 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures