Best time to fly out of Chicago O'Hare (ORD)
The early-flight folk wisdom holds up at Chicago O'Hare: departures in the Before 6am band left on time 89.8% of the time, against 62.1% in the 10pm–12am band. These are historical odds, not forecasts. The records say what happened on this schedule over three years; they know nothing about tomorrow’s thunderstorm.
Data through June 2026 · Bureau of Transportation Statistics
On-time rate by hour and day
On this page, “on time” means a departure that pushed back less than 15 minutes behind its scheduled time — the Bureau of Transportation Statistics definition, and the one airlines are held to.
| Departure time | Mon | Tue | Wed | Thu | Fri | Sat | Sun |
|---|---|---|---|---|---|---|---|
| Before 6am | 88 | 91 | 92 | 92 | 89 | 88 | 89 |
| 6–8am | 88 | 90 | 92 | 90 | 89 | 89 | 89 |
| 8–10am | 83 | 86 | 86 | 85 | 82 | 83 | 82 |
| 10am–12pm | 78 | 82 | 82 | 80 | 77 | 79 | 77 |
| 12–2pm | 78 | 81 | 81 | 79 | 77 | 79 | 76 |
| 2–4pm | 75 | 79 | 77 | 75 | 73 | 78 | 72 |
| 4–6pm | 69 | 75 | 73 | 70 | 69 | 74 | 66 |
| 6–8pm | 68 | 73 | 70 | 67 | 67 | 70 | 65 |
| 8–10pm | 65 | 70 | 68 | 62 | 62 | 68 | 62 |
| 10pm–12am | 61 | 66 | 62 | 61 | 63 | 69 | 57 |
The steadiest stretch at ORD was Before 6am — 89.8% of departures left on time across 9,332 flights. The weakest was 10pm–12am at 62.1%. 6–8am departures from ORD left on time 89.6% of the time across 91,658 flights; 6–8pm departures, 68.4% across 136,135. That is a gap of 21.2 points, and it is the whole case for the early flight.
The year at ORD
July was the hard month at ORD: 66.9% of departures left on time, across 77,830 flights. October was the easy one at 82.2%. Each month pools three years of that month, so a single bad week does not decide it.
| Month | Share departures that left on time | Flights |
|---|---|---|
| January | 74% | 67,095 |
| February | 80.8% | 65,080 |
| March | 75.8% | 78,241 |
| April | 78.5% | 82,988 |
| May | 75.8% | 86,568 |
| June | 71.7% | 85,222 |
| July | 66.9% | 77,830 |
| August | 73.8% | 78,937 |
| September | 80.9% | 76,098 |
| October | 82.2% | 79,119 |
| November | 81.7% | 71,492 |
| December | 75.2% | 71,122 |
Airlines at ORD
Every airline with at least 100 departures from ORD, busiest first. These are that airline’s departures from this airport only — its record across the country sits on its own page.
| Airline | Left on time | Typical delay | Cancelled | Departures |
|---|---|---|---|---|
| United Airlines | 78.1% | 71 min | 1.1% | 279,602 |
| SkyWest Airlines | 74.3% | 87 min | 2.4% | 186,962 |
| American Airlines | 71.8% | 82 min | 1.7% | 162,337 |
| Envoy Air | 79% | 59 min | 1.9% | 123,316 |
| Republic Airways | 83.8% | 71 min | 2.3% | 70,990 |
| Delta Air Lines | 78.2% | 93 min | 1.6% | 32,351 |
| Spirit Airlines | 69.8% | 75 min | 2.2% | 20,572 |
| Southwest Airlines | 76.8% | 60 min | 1.3% | 18,221 |
| Alaska Airlines | 73.5% | 60 min | 1.2% | 9,420 |
| Frontier Airlines | 69.1% | 102 min | 2.9% | 8,935 |
| PSA Airlines | 63% | 137 min | 6.6% | 3,619 |
| JetBlue Airways | 75.7% | 102 min | 2% | 3,368 |
Spirit Airlines (through May 2026) stopped filing before June 2026. Its row covers a shorter run of months than the rest of the table, so its figure is not set against the others anywhere on this page.
What delays out of ORD were put down to
Airlines file a reason with every arrival running 15 minutes late or more. Across 228,679 flights that departed ORD and ran 15 minutes late or more, the delay minutes break down with 40.4% put down to late-arriving aircraft and 30.7% to airline operations.
- Late-arriving aircraft 40.4%
- Airline operations 30.7%
- Air traffic & airport volume 20.5%
- Severe weather 8.3%
- Security 0.1%
Late-arriving aircraft is the knock-on category: the plane came in late, so it went out late again. It is why a 7am problem in Newark is still a problem in Denver at dinnertime, and why it is usually the biggest slice on the bar.
If you are connecting through ORD
Of 919,665 scheduled arrivals into ORD, 75.3% reached the gate less than 15 minutes behind schedule. Of the 207,234 arrivals that ran late, 50.8% were no more than 45 minutes behind — which is the difference between a tight connection and a new boarding pass.
Work out a specific layover — pick the airport and the minutes you have, and the tool reads the same arrival records back as a share.
Busiest routes out of ORD
Ranked by flights, with the share that arrived on time at the far end. Where a route carries enough flights for a page of its own the chip goes there; otherwise it goes to the destination airport.
- LGA 73.7% on time · 32,929 flights
- BOS 72.6% on time · 21,109 flights
- LAX 76.5% on time · 20,424 flights
- DFW 73% on time · 19,767 flights
- DCA 73.1% on time · 19,515 flights
- DEN 77% on time · 18,950 flights
- ATL 75.8% on time · 17,986 flights
- EWR 72% on time · 17,938 flights
- MSP 73.3% on time · 17,746 flights
- PHX 78.1% on time · 17,440 flights
ORD in one number
Chicago O'Hare (ORD)
Rank 4 of 363 US airports by departures. Steadiest stretch of the day: Before 6am. Hardest month: July.
Questions about ORD
- What is the best time of day to fly out of Chicago O'Hare?
- Before 6am. Departures in that band left on time 89.8% of the time across 9,332 flights, July 2023 through June 2026 — the best of the ten bands in the day. The 10pm–12am band was the weakest at 62.1%.
- Is the early flight out of ORD really more reliable?
- 6–8am departures from ORD left on time 89.6% of the time across 91,658 flights; 6–8pm departures, 68.4% across 136,135. That is a gap of 21.2 points, and it is the whole case for the early flight.
- What is the worst month to fly out of ORD?
- July: 66.9% of the departures that flew left on time, with 77,830 scheduled. October was the other end of the year at 82.2%. Each figure pools three years of that calendar month.
- Which airline is most on time at ORD?
- Republic Airways — 83.8% of its 70,990 departures from ORD left on time. PSA Airlines sat at the other end at 63% over 3,619 flights. Only airlines with at least 100 departures here are ranked. Airlines that stopped filing before June 2026 are left out of the ranking — their figures cover a shorter run of months than the rest of the table.
- How often are flights cancelled at ORD?
- 1.8% of scheduled departures were cancelled over July 2023 through June 2026. Cancellations are counted against everything scheduled, not against everything that flew — a rate that looks small still adds up to real people in a rebooking line.