Best Time to Fly IAD to ORD: On-Time Stats by Hour & Airline
Washington Dulles International → Chicago O'Hare International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 75.4% of Washington (IAD) to Chicago (ORD) flights arrived on time (2,085 scheduled flights). That is 2.2 points below the national average of 77.6%.
United Airlines was the only reporting airline with regular flights on this route.
Over 24 months, Saturday was the most reliable day (80% on time) and July the worst month (65%).
The cancellation rate was 1.0% (US average 1.8%).
IAD to ORD on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| United Airlines | 75.4% | 76 min | 1.0% | 2,085 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAD to ORD
On-time arrival % by scheduled departure hour (local time), 3,943 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 93.5% | 0.5% | 561 |
| 7am–8am | Limited data | 3 | |
| 8am–9am | 85.6% | 0.4% | 730 |
| 10am–11am | 91.3% | 0.8% | 127 |
| 12pm–1pm | 88.0% | 0.5% | 201 |
| 1pm–2pm | 80.3% | 0.9% | 529 |
| 3pm–4pm | 64.2% | 0.4% | 267 |
| 5pm–6pm | 53.8% | 1.0% | 730 |
| 6pm–7pm | 39.7% | 0.0% | 63 |
| 7pm–8pm | Limited data | 1 | |
| 8pm–9pm | Limited data | 3 | |
| 10pm–11pm | 79.3% | 1.1% | 724 |
| 11pm–12am | Limited data | 4 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on IAD to ORD
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 73.5% | -5.5 pts | 4.2% | 71 |
| Christmas & New Year (Dec 20 - Jan 3) | 80.0% | +1.0 pts | 0.0% | 135 |
| Summer peak (Jun 15 - Aug 15) | 69.1% | -9.9 pts | 1.4% | 774 |
| All other days | 79.0% | — | 0.5% | 2,963 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).