Route reliability record
PDX→SFO
Portland to San Francisco
- Flights
- 3,516
- Period
- July 2025 to June 2026
- Distance
- 550 mi
- Carriers
- 4
This route sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 3,516 flights, of which SkyWest Airlines flew 458 at 84.2% on time.
SkyWest Airlines is the most reliable of the three carriers covered here at 84.2% on time across 458 flights.
Key figures
On time
72.3%
Arrivals under 15 minutes late, of 3,499 completed flights
Avg delay
58 min
Across delayed arrivals only, not all flights
Cancelled
0.43%
National rate is 1.81%
Best carrier
SkyWest
84.2% on time across 458 flights
These figures cover 3,516 flights between July 2025 and June 2026. The median arrival is 2 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 SFO
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 84.2% of the time; United Airlines manages 69.1%. Sample sizes sit next to every figure, because a two-point gap across 1,661 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 14 | 92.3% | 23 min | 7.14% | A− |
| SkyWest Airlines | 458 | 84.2% | 71 min | 0.44% | B+ |
| Alaska Airlines | 1,383 | 72.0% | 55 min | 0.51% | C+ |
| United Airlines | 1,661 | 69.1% | 59 min | 0.30% | C+ |
The spread between SkyWest and United is 15 points, wide enough that it should decide the booking. On a hundred trips that is 15 more arrivals inside the on-time window.
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 15 points, against 15 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1,045 flights72.8%
- 8am–11am517 flights73.0%
- 11am–2pm449 flights71.1%
- 2pm–5pm568 flights80.4%
- 5pm–8pm770 flights65.6%
- 8pm–5am167 flights72.9%
Scale runs 55% to 85%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 2pm–5pm slot at 80.4% on time, ahead of 5pm–8pm at 65.6%. 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 5am–8am window is the busiest, with 1,045 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 41 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.
Delays peak in May, when the on-time rate falls to 47.7%. March is the strongest month at 88.9%. Moving a flexible trip across that boundary buys 41 points. October was the busiest month here, with 343 flights.
Across the week, Saturday is the strongest day at 80.2% on time and Thursday the weakest at 67.6%. 13 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. National Airspace System accounts for 61% of the 56,000 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.
- 61%National Airspace System
- 25%Late-arriving aircraft
- 14%Carrier
- 0%Extreme weather
- 0%Security
61% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 34,000 minutes out of 56,000, against a national NAS share of 21%. The split is drawn from 56,408 reported delay minutes.
Cancellations are rare at 0.43%, below the national 1.81% 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
7.6% 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 are the about an hour kind, which a normal layover absorbs.
The 550 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 80.4% on time across 3,514 flights, 8 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 8 points of difference.
The sample behind these figures is 3,516 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. March runs 88.9% on time and May 47.7%, a swing of 41 points. If the dates move at all, move them out of May before you think about anything else. 3,499 completed flights over 12 months sit behind that.
Common questions
PDX to SFO questions
How often is PDX to SFO 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 27.7% of the 3,516 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on PDX to SFO?
SkyWest Airlines leads at 84.2% on time across 458 flights. United Airlines is at the other end on 69.1%, a gap of 15 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 SFO?
The 2pm–5pm departure window is the strongest at 80.4% on time. The 5pm–8pm window is the weakest at 65.6%, 15 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 May delays on PDX to SFO?
May is the weakest month at 47.7% on time, compared with 88.9% in March. Across the year that is 41 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
- SFO to PDX — the return legseparate record
- Portland International (PDX) delay statistics
- San Francisco International (SFO) delay statistics
- Frontier Airlines on-time record92.3%
- SkyWest Airlines on-time record84.2%
- Alaska Airlines on-time record72.0%
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. PDX to SFO and SFO 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, July 2025 to June 2026. Updated monthly. How this data is collected.