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DelayAtlas

Airport month record

CMHJUL

John Glenn Columbus International in July 2025

Departures
3,933
Month
July 2025
National, same month
71.1%
Carriers
11
C−GRADE

Historical statistics for July 2025, not live status or a forecast for this year’s July. For today’s conditions at CMH, see live FAA status.

CMH in July carries a cancellation problem, not just a delay problem: 3.4% of scheduled flights never operate, against 2.5% nationally. Of the ones that do fly, close to three flights in four arrive on time, worth a C− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 3,933 flights, of which Delta Air Lines flew 399 at 82.2% on time.

Delta Air Lines is the most reliable of the three carriers covered here at 82.2% on time across 399 flights.

Key figures

On time

73.3%

Arrivals under 15 minutes late, of 3,775 completed departures

Avg delay

79 min

Across delayed arrivals only, not all flights

Cancelled

3.41%

Nationally in July: 2.45%

Whole year

80.1%

CMH across all twelve months

These figures cover 3,933 departures from John Glenn Columbus International in July 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

July next to CMH's other months

Against CMH's own year, July ran 7 points worse than the twelve-month rate of 80.1%, which makes it number eleven of twelve months, best first. Cancellations are where July stands out: 3.41% of scheduled departures were called off, 1.7 times the airport's rate across the year.

CMH month by month
MonthFlightsOn timeAvg delayCancelledGrade
July 2025 (this page)3,93373.3%79 min3.41%C−
August 20253,75882.1%68 min1.41%B
September 20253,72685.2%67 min0.51%A+
October 20254,03181.1%67 min0.72%B+
November 20253,64179.9%77 min1.81%B
December 20253,56770.7%75 min1.68%C
January 20263,29681.6%78 min6.28%B−
February 20263,23182.9%75 min2.72%B
March 20264,01076.4%86 min3.24%B−
April 20263,71384.2%72 min0.51%B+
May 20263,86083.4%65 min1.22%B
June 20263,87681.0%78 min1.57%B

Departure window

The best time of day to leave CMH in July

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 37 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am1,107 flights90.1%
  • 8am–11am602 flights85.5%
  • 11am–2pm582 flights77.2%
  • 2pm–5pm638 flights57.7%
  • 5pm–8pm787 flights53.1%
  • 8pm–5am217 flights55.2%

Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 53.1% on time, against 90.1% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 1,107 flights scheduled in it.

Across the week, Tuesday is the strongest day at 78.8% on time and Sunday the weakest at 66.9%. 12 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week68.4Mon78.8Tue76.6Wed75.1Thu73.4Fri72.0Sat66.9Sun
Monday: 68.4 percent on time. Tuesday: 78.8 percent on time. Wednesday: 76.6 percent on time. Thursday: 75.1 percent on time. Friday: 73.4 percent on time. Saturday: 72.0 percent on time. Sunday: 66.9 percent on time

Carrier by carrier

Which airlines ran best at CMH in July

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 82.2% of the time; Southwest Airlines manages 73.6%. Sample sizes sit next to every figure, because a two-point gap across 1,092 flights means less than a ten-point one.

Carriers at CMH in July 2025
AirlineFlightsOn timeAvg delayCancelledGrade
Southwest Airlines1,09273.6%66 min1.28%C
Republic Airways1,05577.8%80 min6.54%B−
Delta Air Lines39982.2%70 min1.00%B
American Airlinesthin sample35572.1%80 min4.23%C−
United Airlinesthin sample26060.3%85 min0.38%D+
Envoy Airthin sample25573.1%97 min0.39%C+
Spirit Airlinesthin sample15472.1%67 min4.55%C−
PSA Airlinesthin sample14662.9%129 min9.59%D−
SkyWest Airlinesthin sample12458.6%106 min6.45%D−
Alaska Airlinesthin sample6165.0%48 min1.64%C
Frontier Airlinesthin sample3253.1%71 min0.00%F+

Republic Airways cancels 6.5% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

Route by route

Busiest routes out of CMH in July

Routes from CMH in July 2025
RouteFlightsOn timeAvg delayCancelledGrade
CMH to ORD · Chicago39865.3%102 min2.26%C
CMH to ATL · Atlantathin sample29981.4%71 min0.33%B+
CMH to LGA · New Yorkthin sample25275.0%77 min13.49%B−
CMH to DCA · Washingtonthin sample18061.6%109 min10.56%D−
CMH to MCO · Orlandothin sample17873.1%74 min0.56%C+
CMH to BOS · Bostonthin sample17282.4%95 min0.58%B+
CMH to CLT · Charlottethin sample16585.1%81 min2.42%A
CMH to DEN · Denverthin sample16370.7%76 min0.61%C+
CMH to EWR · Newarkthin sample16072.4%75 min8.75%C−
CMH to JFK · New Yorkthin sample15475.4%76 min6.49%B−
CMH to DFW · Dallas-Fort Worththin sample15373.8%70 min3.27%C−
CMH to MDW · Chicagothin sample13171.5%72 min0.76%C+
CMH to PHL · Philadelphiathin sample12753.4%76 min7.87%F−
CMH to DTW · Detroitthin sample12382.0%98 min0.81%B+
CMH to MSP · Minneapolisthin sample11672.6%60 min2.59%C
CMH to PHX · Phoenixthin sample11484.1%123 min0.88%B+
CMH to FLL · Fort Lauderdalethin sample9475.3%62 min1.06%B
CMH to BWI · Baltimorethin sample9283.5%69 min7.61%B−
CMH to BNA · Nashvillethin sample8873.6%50 min1.14%C
CMH to IAD · Washingtonthin sample8574.0%132 min9.41%C−
CMH to MIA · Miamithin sample8271.6%65 min0.00%C+
CMH to LAS · Las Vegasthin sample7875.6%47 min0.00%B+
CMH to TPA · Tampathin sample7075.7%60 min0.00%B+
CMH to SEA · Seattlethin sample6165.0%48 min1.64%C
CMH to STL · St. Louisthin sample5773.7%65 min0.00%C+

Delay causes

What held CMH up in July

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 80,000 reported delay minutes.

  • Late-arriving aircraft
    36%
  • Carrier
    28%
  • National Airspace System
    26%
  • Extreme weather
    9%
  • Security
    0%

36% 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 80,000 reported delay minutes here, that single category outweighs weather by 4 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 79,860 reported delay minutes.

Cancellations run at 3.41%, against 2.45% nationally. That is about one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.5% of arrivals land a full hour or more behind schedule, against 12.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

What to do with this

Flying from CMH in July

For a July trip through CMH: plan on this being one of the airport's harder months. The 5am–8am departures held up best at 90.1% on time, and with 11.5% of arrivals an hour or more late, a connection here deserves more slack than the same trip in September would.

Related

Where to go next

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.