Best time to fly out of John Glenn Columbus (CMH)
The early-flight folk wisdom holds up at John Glenn Columbus: departures in the Before 6am band left on time 93.8% of the time, against 66.1% in the 8–10pm 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 | 94 | 91 | 93 | 94 | 95 | 93 | 94 |
| 6–8am | 91 | 91 | 93 | 93 | 92 | 90 | 92 |
| 8–10am | 88 | 92 | 91 | 91 | 91 | 89 | 91 |
| 10am–12pm | 85 | 89 | 89 | 88 | 87 | 88 | 86 |
| 12–2pm | 80 | 86 | 88 | 83 | 79 | 83 | 81 |
| 2–4pm | 76 | 80 | 81 | 75 | 74 | 78 | 73 |
| 4–6pm | 74 | 79 | 76 | 70 | 73 | 74 | 69 |
| 6–8pm | 72 | 76 | 75 | 70 | 71 | 69 | 66 |
| 8–10pm | 70 | 74 | 72 | 63 | 66 | 66 | 60 |
| 10pm–12am | – | – | – | – | – | – | – |
The steadiest stretch at CMH was Before 6am — 93.8% of departures left on time across 5,721 flights. The weakest was 8–10pm at 66.1%. 6–8am departures from CMH left on time 91.6% of the time across 30,068 flights; 6–8pm departures, 71.2% across 14,917. That is a gap of 20.4 points, and it is the whole case for the early flight.
The year at CMH
July was the hard month at CMH: 75.9% of departures left on time, across 11,475 flights. October was the easy one at 87.2%. 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 | 83.6% | 9,747 |
| February | 84.4% | 9,377 |
| March | 80.9% | 11,231 |
| April | 84.9% | 10,888 |
| May | 81.2% | 11,291 |
| June | 79.1% | 11,431 |
| July | 75.9% | 11,475 |
| August | 83.4% | 11,209 |
| September | 86.9% | 10,760 |
| October | 87.2% | 11,522 |
| November | 86.4% | 10,659 |
| December | 80.5% | 10,414 |
Airlines at CMH
Every airline with at least 100 departures from CMH, 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 |
|---|---|---|---|---|
| Southwest Airlines | 80.3% | 56 min | 0.9% | 36,525 |
| Republic Airways | 88.1% | 67 min | 2.3% | 36,310 |
| American Airlines | 81% | 116 min | 2% | 11,488 |
| Delta Air Lines | 88.2% | 83 min | 1% | 10,331 |
| Envoy Air | 83.5% | 89 min | 0.9% | 9,478 |
| United Airlines | 78.4% | 77 min | 1.1% | 8,796 |
| Spirit Airlines | 75.1% | 70 min | 2.1% | 5,904 |
| PSA Airlines | 78.2% | 94 min | 3% | 4,237 |
| SkyWest Airlines | 79.7% | 99 min | 1.2% | 3,802 |
| Alaska Airlines | 75.1% | 44 min | 1.1% | 1,416 |
| Frontier Airlines | 70.3% | 84 min | 2.5% | 1,032 |
| Endeavor Air | 85.5% | 63 min | 0.4% | 685 |
Spirit Airlines (through May 2026) and Endeavor Air (through December 2024) stopped filing before June 2026. Their rows cover a shorter run of months than the rest of the table, so their figures are not set against the others anywhere on this page.
What delays out of CMH were put down to
Airlines file a reason with every arrival running 15 minutes late or more. Across 22,818 flights that departed CMH and ran 15 minutes late or more, the delay minutes break down with 37.8% put down to late-arriving aircraft and 30.8% to airline operations.
- Late-arriving aircraft 37.8%
- Airline operations 30.8%
- Air traffic & airport volume 27.3%
- Severe weather 4.1%
- 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 CMH
Of 130,020 scheduled arrivals into CMH, 77.3% reached the gate less than 15 minutes behind schedule. Of the 27,295 arrivals that ran late, 54.5% 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 CMH
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.
- ORD 77.4% on time · 11,694 flights
- ATL 86.5% on time · 9,498 flights
- LGA 83.7% on time · 9,231 flights
- MCO 80.5% on time · 6,591 flights
- CLT 79.4% on time · 6,040 flights
- DCA 77.1% on time · 5,934 flights
- EWR 86.2% on time · 5,746 flights
- BOS 84.3% on time · 5,602 flights
- DEN 80.4% on time · 5,382 flights
- JFK 86.1% on time · 5,274 flights
CMH in one number
John Glenn Columbus (CMH)
Rank 43 of 363 US airports by departures. Steadiest stretch of the day: Before 6am. Hardest month: July.
Questions about CMH
- What is the best time of day to fly out of John Glenn Columbus?
- Before 6am. Departures in that band left on time 93.8% of the time across 5,721 flights, July 2023 through June 2026 — the best of the ten bands in the day. The 8–10pm band was the weakest at 66.1%.
- Is the early flight out of CMH really more reliable?
- 6–8am departures from CMH left on time 91.6% of the time across 30,068 flights; 6–8pm departures, 71.2% across 14,917. That is a gap of 20.4 points, and it is the whole case for the early flight.
- What is the worst month to fly out of CMH?
- July: 75.9% of the departures that flew left on time, with 11,475 scheduled. October was the other end of the year at 87.2%. Each figure pools three years of that calendar month.
- Which airline is most on time at CMH?
- Delta Air Lines — 88.2% of its 10,331 departures from CMH left on time. Frontier Airlines sat at the other end at 70.3% over 1,032 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 CMH?
- 1.5% 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.