Route reliability record
SFO→PDX
San Francisco to Portland
- Flights
- 3,491
- Period
- September 2025 to August 2026
- Distance
- 550 mi
- Carriers
- 3
This route lands a B+, level with the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 3,491 SFO to PDX flights, of which United Airlines flew 1,726 at 78.8% on time.
Best time to fly SFO to PDX: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 96.4% of the time and Saturday flights 85.6%, against 78.0% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.0%
Arrivals under 15 minutes late, of 3,480 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
0.32%
National rate is 1.89%
Best carrier
United
78.8% on time across 1,726 flights
These figures cover 3,491 flights between September 2025 and August 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.
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Carrier by carrier
Which airline is most reliable on SFO to PDX
The two carriers here are closely matched: 2 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,726 | 78.8% | 62 min | 0.12% | B+ |
| SkyWest Airlinesthin sample | 363 | 78.7% | 56 min | 0.28% | B+ |
| Alaska Airlines | 1,402 | 76.8% | 55 min | 0.57% | B+ |
No carrier stands out. United tops the table at 78.8%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on SFO to PDX
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly San Francisco to Portland
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 3 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SJC → PDXSan Jose to Portland | SkyWest Airlines | 91.1% | 91.1% | 0.00% | 11am–2pm, Wed | — |
| 2. SJC → PDXSan Jose to Portland | Southwest Airlines | 80.0% | 80.0% | 0.00% | 5am–8am, Wed | — |
| 3. SFO → PDXSan Francisco to Portland | United Airlines | 78.7% | 78.8% | 0.12% | 5am–8am, Sat | — |
| 4. OAK → PDXOakland to Portland | Southwest Airlines | 78.2% | 78.5% | 0.44% | 8am–11am, Tue | — |
| 5. SFO → PDXSan Francisco to Portland | Alaska Airlines | 76.4% | 76.8% | 0.57% | 5am–8am, Sat | AS 1410 08:00 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 24 points, against 2 points between the best and worst carrier.
- 5am–8am197 flights96.4%
- 8am–11am649 flights83.0%
- 11am–2pm671 flights72.0%
- 2pm–5pm651 flights73.0%
- 5pm–8pm674 flights79.6%
- 8pm–5am649 flights77.0%
Scale runs 65% to 100%.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 72.0% on time against 96.4% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 5pm–8pm window is the busiest, with 674 flights scheduled in it.
Explore
Filter SFO to PDX by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SFO to PDX, the best departure window is 5am–8am at 96.4% on time and the worst is 11am–2pm at 72.0%, a wide gap of 24.4 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am96.4%
- 8–11am83.0%
- 11am–2pm72.0%
- 2–5pm73.0%
- 5–8pm79.6%
- 8pm–5am77.0%
best all US flightsScale 60% to 100%.
Across the year
When delays peak on this route
This route's year swings by 21 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 67.9%. March is the strongest month at 89.2%. Moving a flexible trip across that boundary buys 21 points. October was the busiest month here, with 344 flights.
Across the week, Saturday is the strongest day at 85.6% on time and Thursday the weakest at 70.6%, a spread of 15 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 62% of the 45,000 delay minutes carriers reported here, and the remaining four split what is left.
- 62%Late-arriving aircraft
- 27%Carrier
- 10%National Airspace System
- 0%Extreme weather
- 0%Security
62% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 45,000 reported delay minutes here, that single category outweighs weather by 62 to one. The split is drawn from 44,786 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 96.4% on time here.
Cancellations are rare at 0.32%, below the national 1.89% 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
6.4% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, 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.
The return leg is a different operation and performs like one: it runs 66.8% on time across 3,495 flights, 11 points below 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 11 points of difference.
The sample behind these figures is 3,491 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.
Work out the risk of missing a connection in PDX after this flight
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 89.2% on time and May 67.9%, a swing of 21 points. If the dates move at all, move them out of May before you think about anything else. 3,480 completed flights over 12 months sit behind that.
Common questions
SFO to PDX questions
How often is SFO to PDX delayed?
Roughly one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.0% of the 3,491 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on SFO to PDX?
United Airlines leads at 78.8% on time across 1,726 flights. Alaska Airlines is at the other end on 76.8%, a gap of 2 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 SFO to PDX?
The 5am–8am departure window is the strongest at 96.4% on time. The 11am–2pm window is the weakest at 72.0%, 24 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 SFO to PDX?
May is the weakest month at 67.9% on time, compared with 89.2% in March. Across the year that is 21 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 SFO — the return legseparate record
- San Francisco International (SFO) delay statistics
- Portland International (PDX) delay statistics
- United Airlines on SFO to PDX78.8%
- SkyWest Airlines on SFO to PDX78.7%
- Alaska Airlines on SFO to PDX76.8%
- SFO to LAX, a related route70.9%
- SEA to PDX, a related route82.2%
- SFO to SEA, a related route72.3%
- United Airlines on-time record78.8%
- SkyWest Airlines on-time record78.7%
- Alaska Airlines on-time record76.8%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. SFO to PDX and PDX to SFO are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.