Route reliability record
PWM→ORD
Portland to Chicago
- Flights
- 1,486
- Period
- July 2025 to June 2026
- Distance
- 900 mi
- Carriers
- 4
This route carries a cancellation problem, not just a delay problem: 3.2% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, close to three flights in four arrive on time, worth a B− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 1,486 PWM to ORD flights, of which Republic Airways flew 558 at 82.3% on time.
Best time to fly PWM to ORD: a 5am–8am departure, ideally on a Friday. Flights in that window arrived on time 89.2% of the time and Friday flights 82.5%, against 77.2% for the route overall.
The US average over the same twelve months is 77.6%, 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
77.2%
Arrivals under 15 minutes late, of 1,433 completed flights
Avg delay
90 min
Across delayed arrivals only, not all flights
Cancelled
3.23%
National rate is 1.81%
Best carrier
Republic
82.3% on time across 558 flights
These figures cover 1,486 flights between July 2025 and June 2026. Beyond the headline rate, 8.3% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on PWM to ORD
The two 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 |
|---|---|---|---|---|---|
| Republic Airways | 558 | 82.3% | 83 min | 3.41% | B− |
| Envoy Airthin sample | 200 | 82.2% | 97 min | 4.00% | B− |
| United Airlines | 428 | 76.6% | 94 min | 2.10% | B |
| SkyWest Airlinesthin sample | 300 | 65.2% | 89 min | 4.00% | C− |
Republic Airways cancels 3.4% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
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. PWM → ORDPortland to Chicago | Republic Airways | 79.5% | 82.3% | 3.41% | 8am–11am, Fri | — |
| 2. PWM → ORDPortland to Chicago | United Airlines | 75.0% | 76.6% | 2.10% | 5am–8am, Fri | — |
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 6 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am482 flights89.2%
- 8am–11am83 flights88.9%
- 11am–2pm183 flights86.7%
- 2pm–5pm252 flights66.1%
- 5pm–8pm486 flights65.1%
- 8pm–5am—
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 89.2% of the time, against 65.1% for the evening window. That is 24 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 486 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 30 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.
January is the weak month at 58.8% on time, against 88.5% in May. 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. August was the busiest month here, with 177 flights.
Across the week, Friday is the strongest day at 82.5% on time and Wednesday the weakest at 74.0%. 9 points is a smaller lever than departure hour, but it is free.
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 29,000 reported delay minutes.
- 39%National Airspace System
- 35%Carrier
- 18%Late-arriving aircraft
- 8%Extreme weather
- 0%Security
39% 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 11,000 minutes out of 29,000, against a national NAS share of 21%. The split is drawn from 29,270 reported delay minutes.
The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 10,000 of the 29,000 delay minutes reported here.
Cancellations run at 3.23%, against 1.81% nationally. That is about one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here actually costs
8.3% 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 last an hour and a half, which a normal layover absorbs.
The 900 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 74.0% on time across 1,486 flights, 3 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 3 points of difference.
The sample behind these figures is 1,486 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 delay figures matter less here than the 3.23% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 1,433 completed flights over 12 months sit behind that.
Common questions
PWM to ORD questions
How often is PWM to ORD delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.8% of the 1,486 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on PWM to ORD?
Republic Airways leads at 82.3% on time across 558 flights. United Airlines is at the other end on 76.6%, 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 PWM to ORD?
The 5am–8am departure window is the strongest at 89.2% on time. The 5pm–8pm window is the weakest at 65.1%, 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 January delays on PWM to ORD?
January is the weakest month at 58.8% on time, compared with 88.5% in May. Across the year that is 30 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 PWM — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Republic Airways on PWM to ORD82.3%
- Envoy Air on PWM to ORD82.2%
- United Airlines on PWM to ORD76.6%
- SkyWest Airlines on PWM to ORD65.2%
- PWM to BWI, a related route81.8%
- LGA to ORD, a related route67.3%
- PWM to DCA, a related route74.5%
- Republic Airways on-time record82.3%
- Envoy Air on-time record82.2%
- United Airlines on-time record76.6%
- The US routes with the most cancellations
- The best time of day to fly, according to 7.04 million flight records
Direction matters. PWM to ORD and ORD to PWM 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.