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DelayAtlas

Route reliability record

PDXSJC

Portland to San Jose

Flights
1,636
Period
July 2025 to June 2026
Distance
569 mi
Carriers
3
B+GRADE

This route lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That is a workable record, not a spotless one. That rests on 1,636 PDX to SJC flights, of which SkyWest Airlines flew 499 at 88.1% on time.

Best time to fly PDX to SJC: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 95.5% of the time and Wednesday flights 87.8%, against 82.3% for the route overall.

Set against the rest of the country, this route's record is 5 points better than the US average of 77.6%. That gap is worth roughly 47 fewer late arrivals for every thousand flights.

Key figures

On time

82.3%

Arrivals under 15 minutes late, of 1,630 completed flights

Avg delay

54 min

Across delayed arrivals only, not all flights

Cancelled

0.24%

National rate is 1.81%

Best carrier

SkyWest

88.1% on time across 499 flights

These figures cover 1,636 flights between July 2025 and June 2026. The median arrival is 5 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 SJC

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 88.1% of the time; Southwest Airlines manages 77.3%. Sample sizes sit next to every figure, because a two-point gap across 973 flights means less than a ten-point one.

On-time performance by carrier on PDX to SJC
AirlineFlightsOn timeAvg delayCancelledGrade
Alaska Airlinesthin sample16493.9%85 min0.00%A+
SkyWest Airlines49988.1%53 min0.00%A+
Southwest Airlines97377.3%53 min0.41%B+

SkyWest leads Southwest by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Best ways to make this trip

The most reliable ways to fly Portland to San Jose

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.

Most reliable ways to fly from PDX to SJC
OptionAirlineSuccessOn timeCancelledBest departureMost punctual flight
1. PDXSJCPortland to San JoseSkyWest Airlines88.1%88.1%0.00%5pm–8pm, Wed
2. PDXSFOPortland to San FranciscoSkyWest Airlines83.8%84.2%0.44%5am–8am, Sat
3. PDXSJCPortland to San JoseSouthwest Airlines77.0%77.3%0.41%5am–8am, Sat
4. PDXOAKPortland to OaklandSouthwest Airlines75.2%75.8%0.76%5am–8am, Wed (route)
5. PDXSFOPortland to San FranciscoAlaska Airlines71.6%72.0%0.51%2pm–5pm, SatAS 128 10:30

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.

Plan this trip by month, day and time

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 29 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am360 flights95.5%
  • 8am–11am154 flights90.3%
  • 11am–2pm160 flights84.4%
  • 2pm–5pm413 flights85.4%
  • 5pm–8pm295 flights70.1%
  • 8pm–5am254 flights66.4%

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 95.5% of the time, against 66.4% for the overnight window. That is 29 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 413 flights scheduled in it.

Across the year

When delays peak on this route

Twelve months, one bar each, drawn from the same 1,636 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.

On-time rate by calendar month87J88F86M86A84M81J77J81A79S79O83N81D
Darker means more delays. Figures are on-time percentages.February best, July worst

July is the worst month at 76.5% on time, 12 points below February, the best at 88.3%. 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. December was the busiest month here, with 184 flights.

Across the week, Wednesday is the strongest day at 87.8% on time and Thursday the weakest at 79.6%. 8 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week79.6Mon81.3Tue87.8Wed79.6Thu80.2Fri87.4Sat82.2Sun
Monday: 79.6 percent on time. Tuesday: 81.3 percent on time. Wednesday: 87.8 percent on time. Thursday: 79.6 percent on time. Friday: 80.2 percent on time. Saturday: 87.4 percent on time. Sunday: 82.2 percent on time

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 64% of the 16,000 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.

  • Late-arriving aircraft
    64%
  • Carrier
    30%
  • National Airspace System
    4%
  • Extreme weather
    2%
  • Security
    0%

64% 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 16,000 reported delay minutes here, that single category outweighs weather by 35 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 15,635 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 95.5% on time here.

Cancellations are rare at 0.24%, 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

Badly late arrivals are rare here: only 4.8% land an hour or more behind schedule, against 8.1% 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 569 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 84.9% on time across 1,621 flights, within 3 points 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 1,636 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 SJC after this flight

What to do with this

Booking this route

Put together: avoid the 8pm–5am departure. It runs 66.4% on time against 95.5% for the 5am–8am slot, and that 29 points is the largest single thing you control here. SkyWest Airlines is the strongest operator if the fares are close. 1,630 completed flights over 12 months sit behind that.

Common questions

PDX to SJC questions

How often is PDX to SJC delayed?

About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 17.7% of the 1,636 flights in this analysis, against 22.4% nationally. Delayed flights are late by about 55 minutes on average.

Which airline is most reliable on PDX to SJC?

SkyWest Airlines leads at 88.1% on time across 499 flights. Southwest Airlines is at the other end on 77.3%, 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 SJC?

The 5am–8am departure window is the strongest at 95.5% on time. The 8pm–5am window is the weakest at 66.4%, 29 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 PDX to SJC?

July is the weakest month at 76.5% on time, compared with 88.3% in February. 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

Direction matters. PDX to SJC and SJC to PDX 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.