Airport month record
ORDSEP
Chicago O'Hare International in September 2025
- Departures
- 28,867
- Month
- September 2025
- National, same month
- 83.4%
- Carriers
- 12
Historical statistics for September 2025, not live status or a forecast for this year’s September. For today’s conditions at ORD, see live FAA status.
ORD in September lands a B+, 4 points worse than the national rate of 83.4%. 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 is a workable record, not a spotless one. That rests on 28,867 flights, of which Spirit Airlines flew 471 at 87.8% on time.
Spirit Airlines is the most reliable of the eight carriers covered here at 87.8% on time across 471 flights.
Key figures
On time
79.2%
Arrivals under 15 minutes late, of 28,678 completed departures
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
0.42%
Nationally in September: 0.51%
Whole year
71.0%
ORD across all twelve months
These figures cover 28,867 departures from Chicago O'Hare International in September 2025. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.
Against the year
September next to ORD's other months
Against ORD's own year, September ran 8 points better than the twelve-month rate of 71.0%, which makes it the best of the twelve months in the data. Cancellations were unusually low for ORD in September, at 0.42% against 2.68% across the year. Either side of it, August ran 73.9% on time and October 74.7%, so a trip moved by a few weeks would have landed in a worse stretch.
| Month | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| July 2025 | 30,503 | 63.9% | 82 min | 2.60% | D |
| August 2025 | 30,090 | 73.9% | 80 min | 2.48% | C |
| September 2025 (this page) | 28,867 | 79.2% | 68 min | 0.42% | B+ |
| October 2025 | 31,096 | 74.7% | 64 min | 0.23% | C+ |
| November 2025 | 28,703 | 73.3% | 82 min | 5.59% | C− |
| December 2025 | 27,790 | 61.0% | 91 min | 2.53% | D |
| January 2026 | 25,131 | 67.4% | 79 min | 3.74% | C− |
| February 2026 | 25,538 | 73.7% | 67 min | 1.11% | C |
| March 2026 | 31,373 | 65.9% | 85 min | 5.71% | C− |
| April 2026 | 33,206 | 69.7% | 75 min | 3.54% | C− |
| May 2026 | 33,733 | 76.1% | 73 min | 1.01% | B |
| June 2026 | 31,374 | 71.3% | 80 min | 3.19% | C− |
Departure window
The best time of day to leave ORD in September
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 20 points, against 15 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am3,054 flights91.2%
- 8am–11am6,348 flights85.3%
- 11am–2pm4,782 flights82.4%
- 2pm–5pm5,779 flights74.3%
- 5pm–8pm5,336 flights71.6%
- 8pm–5am3,568 flights73.2%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 91.2% of the time, against 71.6% for the evening window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 6,348 flights scheduled in it.
Across the week, Tuesday is the strongest day at 85.8% on time and Saturday the weakest at 68.8%. 17 points is a smaller lever than departure hour, but it is free.
Carrier by carrier
Which airlines ran best at ORD in September
The choice of carrier is not cosmetic here. Spirit Airlines arrives on time 87.8% of the time; American Airlines manages 72.6%. Sample sizes sit next to every figure, because a two-point gap across 5,100 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 8,878 | 79.1% | 65 min | 0.16% | B+ |
| SkyWest Airlines | 6,195 | 77.4% | 65 min | 0.65% | B+ |
| American Airlines | 5,100 | 72.6% | 79 min | 0.45% | C+ |
| Envoy Air | 4,048 | 85.5% | 49 min | 0.59% | A+ |
| Republic Airways | 1,846 | 87.1% | 59 min | 0.22% | A+ |
| Delta Air Lines | 1,012 | 81.6% | 78 min | 0.20% | B+ |
| Spirit Airlines | 471 | 87.8% | 57 min | 0.42% | A+ |
| Southwest Airlines | 395 | 83.2% | 59 min | 0.25% | B+ |
| Frontier Airlinesthin sample | 333 | 78.0% | 130 min | 1.20% | B |
| PSA Airlinesthin sample | 249 | 70.6% | 97 min | 1.61% | C |
| Alaska Airlinesthin sample | 243 | 80.8% | 72 min | 0.82% | B+ |
| JetBlue Airwaysthin sample | 97 | 81.4% | 88 min | 0.00% | B+ |
The spread between Spirit and American is 15 points, wide enough that it should decide the booking. On a hundred trips that is 15 more arrivals inside the on-time window.
Route by route
Busiest routes out of ORD in September
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| ORD to LGA · New York | 972 | 76.4% | 72 min | 0.31% | B+ |
| ORD to BOS · Boston | 660 | 56.2% | 79 min | 0.61% | D+ |
| ORD to LAX · Los Angeles | 616 | 81.3% | 77 min | 0.32% | B+ |
| ORD to DEN · Denver | 605 | 80.4% | 72 min | 0.17% | B+ |
| ORD to DCA · Washington | 576 | 67.6% | 71 min | 0.69% | C+ |
| ORD to ATL · Atlanta | 543 | 87.3% | 89 min | 0.00% | A+ |
| ORD to MSP · Minneapolis | 536 | 71.2% | 63 min | 0.37% | C+ |
| ORD to DFW · Dallas-Fort Worth | 535 | 77.6% | 87 min | 1.50% | B |
| ORD to IAH · Houston | 532 | 84.2% | 76 min | 0.19% | B+ |
| ORD to SEA · Seattle | 509 | 84.2% | 67 min | 0.39% | B+ |
| ORD to SFO · San Francisco | 490 | 77.6% | 74 min | 0.00% | B+ |
| ORD to DTW · Detroit | 482 | 79.4% | 66 min | 0.21% | B+ |
| ORD to LAS · Las Vegas | 481 | 79.2% | 67 min | 0.62% | B+ |
| ORD to EWR · Newark | 473 | 72.5% | 84 min | 1.48% | C |
| ORD to MCO · Orlando | 454 | 86.1% | 49 min | 0.22% | A+ |
| ORD to PHX · Phoenix | 435 | 75.7% | 87 min | 1.15% | B |
| ORD to PHL · Philadelphia | 412 | 75.5% | 82 min | 0.00% | B+ |
| ORD to CMH · Columbus | 411 | 75.9% | 57 min | 0.24% | B+ |
| ORD to CVG · Cincinnati | 404 | 80.3% | 54 min | 0.74% | B+ |
| ORD to CLE · Cleveland | 403 | 77.1% | 66 min | 0.25% | B+ |
| ORD to BNA · Nashville | 397 | 79.8% | 75 min | 0.25% | B+ |
| ORD to MKE · Milwaukee | 394 | 73.3% | 70 min | 1.02% | C |
| ORD to IND · Indianapolis | 389 | 82.4% | 50 min | 0.77% | B+ |
| ORD to PIT · Pittsburghthin sample | 345 | 85.2% | 59 min | 0.29% | A+ |
| ORD to CLT · Charlottethin sample | 338 | 79.8% | 59 min | 0.30% | B+ |
Delay causes
What held ORD up in September
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 405,000 reported delay minutes.
- 41%Late-arriving aircraft
- 37%Carrier
- 17%National Airspace System
- 6%Extreme weather
- 0%Security
41% 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 405,000 reported delay minutes here, that single category outweighs weather by 7 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 405,102 reported delay minutes.
Cancellations are rare at 0.42%, below the national 0.51% 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.
7.2% of arrivals land an hour or more late, close to the national 5.4%. 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 a little over an hour, which a normal layover absorbs.
What to do with this
Flying from ORD in September
For a September trip through ORD: this is one of the better months to be flying from here, 79.2% on time with 0.42% cancelled. That is a base rate for the month as a whole; a single storm can still spoil a particular day.
Related
Where to go next
- Chicago O'Hare International (ORD), the whole year
- ORD in July63.9%
- ORD in August73.9%
- ORD in October74.7%
- ORD in November73.3%
- ORD in December61.0%
- ORD in January67.4%
- ORD in February73.7%
- ORD in March65.9%
- ORD in April69.7%
- ORD in May76.1%
- ORD in June71.3%
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.