Route reliability record
ORD→PDX
Chicago to Portland
- Flights
- 2,811
- Period
- September 2025 to August 2026
- Distance
- 1,739 mi
- Carriers
- 3
This route draws a C+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 2,811 ORD to PDX flights, of which United Airlines flew 1,414 at 71.8% on time.
Best time to fly ORD to PDX: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 81.1% of the time and Tuesday flights 71.9%, against 67.6% for the route overall.
United Airlines is the most reliable of the three carriers covered here at 71.8% on time across 1,414 flights.
Key figures
On time
67.6%
Arrivals under 15 minutes late, of 2,782 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
0.85%
National rate is 1.89%
Best carrier
United
71.8% on time across 1,414 flights
These figures cover 2,811 flights between September 2025 and August 2026. Beyond the headline rate, 11.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on ORD to PDX
The choice of carrier is not cosmetic here. United Airlines arrives on time 71.8% of the time; American Airlines manages 59.3%. Sample sizes sit next to every figure, because a two-point gap across 899 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,414 | 71.8% | 63 min | 0.57% | C+ |
| Alaska Airlines | 498 | 70.7% | 60 min | 1.20% | C |
| American Airlines | 899 | 59.3% | 77 min | 1.11% | D |
The spread between United and American is 13 points, wide enough that it should decide the booking. On a hundred trips that is 13 more arrivals inside the on-time window.
Flight by flight
Flights on ORD 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 Chicago to Portland
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. ORD → PDXChicago to Portland | United Airlines | 71.4% | 71.8% | 0.57% | 5am–8am, Sat | UA 1994 09:05 |
| 2. ORD → PDXChicago to Portland | Alaska Airlines | 69.9% | 70.7% | 1.20% | 5am–8am, Sat | AS 325 14:12 |
| 3. ORD → PDXChicago to Portland | American Airlines | 58.6% | 59.3% | 1.11% | 5am–8am, Tue | — |
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 34 points, against 13 points between the best and worst carrier.
- 5am–8am318 flights78.8%
- 8am–11am578 flights81.1%
- 11am–2pm395 flights68.2%
- 2pm–5pm743 flights65.6%
- 5pm–8pm132 flights47.3%
- 8pm–5am645 flights55.9%
Scale runs 40% to 85%.
The 5pm–8pm window is where this operation falls apart: 47.3% on time, against 81.1% for the 8am–11am 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. The 2pm–5pm window is the busiest, with 743 flights scheduled in it.
Explore
Filter ORD 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 ORD to PDX, the best departure window is 8am–11am at 81.1% on time and the worst is 5pm–8pm at 47.3%, a wide gap of 33.8 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am78.8%
- 8–11am81.1%
- 11am–2pm68.2%
- 2–5pm65.6%
- 5–8pm47.3%
- 8pm–5am55.9%
best all US flightsScale 40% to 95%.
Across the year
When delays peak on this route
This route's year swings by 29 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.
December is the weak month at 56.4% on time, against 85.2% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. July was the busiest month here, with 339 flights.
Across the week, Tuesday is the strongest day at 71.9% on time and Sunday the weakest at 64.0%, a spread of 8 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 50% of the 61,000 delay minutes carriers reported here, and the remaining four split what is left.
- 50%Late-arriving aircraft
- 26%Carrier
- 19%National Airspace System
- 5%Extreme weather
- 0%Security
50% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 61,000 reported delay minutes here, that single category outweighs weather by 9 to one. The split is drawn from 61,171 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 81.1% on time here.
Cancellations are rare at 0.85%, 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
11.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 1,739 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 79.2% on time across 2,814 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.
The sample behind these figures is 2,811 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. September runs 85.2% on time and December 56.4%, a swing of 29 points. If the dates move at all, move them out of December before you think about anything else. 2,782 completed flights over 12 months sit behind that.
Common questions
ORD to PDX questions
How often is ORD to PDX delayed?
About one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 32.4% of the 2,811 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on ORD to PDX?
United Airlines leads at 71.8% on time across 1,414 flights. American Airlines is at the other end on 59.3%, a gap of 13 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 ORD to PDX?
The 8am–11am departure window is the strongest at 81.1% on time. The 5pm–8pm window is the weakest at 47.3%, 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 December delays on ORD to PDX?
December is the weakest month at 56.4% on time, compared with 85.2% in September. Across the year that is 29 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 ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Portland International (PDX) delay statistics
- United Airlines on ORD to PDX71.8%
- Alaska Airlines on ORD to PDX70.7%
- American Airlines on ORD to PDX59.3%
- ORD to LGA, a related route66.6%
- SEA to PDX, a related route82.2%
- ORD to BOS, a related route66.6%
- United Airlines on-time record71.8%
- Alaska Airlines on-time record70.7%
- American Airlines on-time record59.3%
- Why the first flight of the morning is statistically safest
- Same route, different airline: where the carrier you pick matters most
Direction matters. ORD to PDX and PDX to ORD 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.