Route reliability record
PDX→ORD
Portland to Chicago
- Flights
- 2,814
- Period
- September 2025 to August 2026
- Distance
- 1,739 mi
- Carriers
- 3
This route lands a B, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 2,814 PDX to ORD flights, of which United Airlines flew 1,413 at 81.4% on time.
Best time to fly PDX to ORD: a 8pm–5am departure, ideally on a Wednesday. Flights in that window arrived on time 86.0% of the time and Wednesday flights 80.8%, against 79.2% for the route overall.
United Airlines is the most reliable of the three carriers covered here at 81.4% on time across 1,413 flights.
Key figures
On time
79.2%
Arrivals under 15 minutes late, of 2,768 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
1.00%
National rate is 1.89%
Best carrier
United
81.4% on time across 1,413 flights
These figures cover 2,814 flights between September 2025 and August 2026. The median arrival is 7 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 PDX to ORD
The three carriers here are closely matched: 6 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 | 1,413 | 81.4% | 65 min | 0.71% | B+ |
| Alaska Airlines | 500 | 78.9% | 44 min | 1.40% | B |
| American Airlines | 901 | 75.8% | 104 min | 1.22% | B |
No carrier stands out. United tops the table at 81.4%, 6 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on PDX to ORD
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 Portland to Chicago
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. PDX → ORDPortland to Chicago | United Airlines | 80.8% | 81.4% | 0.71% | 8pm–5am, Sat | UA 1490 23:59 |
| 2. PDX → ORDPortland to Chicago | Alaska Airlines | 77.8% | 78.9% | 1.40% | 8pm–5am, Wed | AS 324 07:00 |
| 3. PDX → ORDPortland to Chicago | American Airlines | 74.9% | 75.8% | 1.22% | 5am–8am, Mon | — |
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 22 points, against 6 points between the best and worst carrier.
- 5am–8am893 flights82.4%
- 8am–11am331 flights78.8%
- 11am–2pm536 flights71.2%
- 2pm–5pm257 flights64.2%
- 5pm–8pm4 flights—
- 8pm–5am793 flights86.0%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
The overnight block holds up unusually well at 86.0% on time across 793 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 5am–8am window is the busiest, with 893 flights scheduled in it.
Explore
Filter PDX to ORD 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 PDX to ORD, the best departure window is 8pm–5am at 86.0% on time and the worst is 2pm–5pm at 64.2%, a wide gap of 21.8 points. All US flights leaving 8pm–5am ran 70.1%.
- 5–8am82.4%
- 8–11am78.8%
- 11am–2pm71.2%
- 2–5pm64.2%
- 5–8pm—
- 8pm–5am86.0%
best all US flightsScale 55% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 16 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 April, when the on-time rate falls to 73.6%. February is the strongest month at 89.8%. Moving a flexible trip across that boundary buys 16 points. July was the busiest month here, with 339 flights.
Across the week, Wednesday is the strongest day at 80.8% on time and Sunday the weakest at 76.7%, a spread of 4 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 44,000 reported delay minutes.
- 38%National Airspace System
- 34%Carrier
- 27%Late-arriving aircraft
- 1%Extreme weather
38% 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 17,000 minutes out of 44,000, against a national NAS share of 21%. The split is drawn from 43,584 reported delay minutes.
Cancellations sit at 1.00% against a national 1.89%, which is ordinary. Diversions add another 0.64%.
Connections and stage length
What a delay here actually costs
6.6% 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 a little over an hour, which a normal layover absorbs.
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 67.6% on time across 2,811 flights, 12 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 12 points of difference.
The sample behind these figures is 2,814 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 ORD 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. February runs 89.8% on time and April 73.6%, a swing of 16 points. If the dates move at all, move them out of April before you think about anything else. 2,768 completed flights over 12 months sit behind that.
Common questions
PDX to ORD questions
How often is PDX to ORD delayed?
About 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 20.8% of the 2,814 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on PDX to ORD?
United Airlines leads at 81.4% on time across 1,413 flights. American Airlines is at the other end on 75.8%, a gap of 6 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 ORD?
The 8pm–5am departure window is the strongest at 86.0% on time. The 2pm–5pm window is the weakest at 64.2%, 22 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 April delays on PDX to ORD?
April is the weakest month at 73.6% on time, compared with 89.8% in February. Across the year that is 16 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
- ORD to PDX — the return legseparate record
- Portland International (PDX) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- United Airlines on PDX to ORD81.4%
- Alaska Airlines on PDX to ORD78.9%
- American Airlines on PDX to ORD75.8%
- PDX to SEA, a related route84.9%
- LGA to ORD, a related route66.7%
- PDX to LAX, a related route86.6%
- United Airlines on-time record81.4%
- Alaska Airlines on-time record78.9%
- American Airlines on-time record75.8%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. PDX to ORD and ORD 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.