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.

Share of departures that left on time, by hour band and day of week.
Departure time MonTueWedThuFriSatSun
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 – – – – – – –
fewer left on time more left on time

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.

Share of departures that left on time, by calendar month. Best month in green, worst in amber. The hairline sits at the overall rate, 82.8%.
Departure on-time share at CMH by calendar month
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

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 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.

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.

July 2023–June 2026 · 128,006 departures flown

82.8% of departures left on time

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.
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.