Airport month record
CMHAUG
John Glenn Columbus International in August 2025
- Departures
- 3,758
- Month
- August 2025
- National, same month
- 77.4%
- Carriers
- 11
Historical statistics for August 2025, not live status or a forecast for this year’s August. For today’s conditions at CMH, see live FAA status.
CMH in August lands a B, 5 points better than the national rate of 77.4%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 3,758 flights, of which Delta Air Lines flew 379 at 88.4% on time.
Delta Air Lines is the most reliable of the three carriers covered here at 88.4% on time across 379 flights.
Key figures
On time
82.1%
Arrivals under 15 minutes late, of 3,697 completed departures
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
1.41%
Nationally in August: 1.08%
Whole year
80.1%
CMH across all twelve months
These figures cover 3,758 departures from John Glenn Columbus International in August 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
August next to CMH's other months
Against CMH's own year, August ran 2 points better than the twelve-month rate of 80.1%, which makes it number five of twelve months, best first. Either side of it, July ran 73.3% on time and September 85.2%, so a trip moved by a few weeks would have landed in a worse stretch.
| Month | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| July 2025 | 3,933 | 73.3% | 79 min | 3.41% | C− |
| August 2025 (this page) | 3,758 | 82.1% | 68 min | 1.41% | B |
| September 2025 | 3,726 | 85.2% | 67 min | 0.51% | A+ |
| October 2025 | 4,031 | 81.1% | 67 min | 0.72% | B+ |
| November 2025 | 3,641 | 79.9% | 77 min | 1.81% | B |
| December 2025 | 3,567 | 70.7% | 75 min | 1.68% | C |
| January 2026 | 3,296 | 81.6% | 78 min | 6.28% | B− |
| February 2026 | 3,231 | 82.9% | 75 min | 2.72% | B |
| March 2026 | 4,010 | 76.4% | 86 min | 3.24% | B− |
| April 2026 | 3,713 | 84.2% | 72 min | 0.51% | B+ |
| May 2026 | 3,860 | 83.4% | 65 min | 1.22% | B |
| June 2026 | 3,876 | 81.0% | 78 min | 1.57% | B |
Departure window
The best time of day to leave CMH in August
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 25 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1,018 flights90.8%
- 8am–11am587 flights90.7%
- 11am–2pm689 flights85.1%
- 2pm–5pm598 flights72.6%
- 5pm–8pm735 flights70.7%
- 8pm–5am131 flights65.9%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.8% of the time, against 65.9% for the overnight window. That is 25 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 1,018 flights scheduled in it.
Across the week, Tuesday is the strongest day at 88.7% on time and Sunday the weakest at 77.2%. 12 points is a smaller lever than departure hour, but it is free.
Carrier by carrier
Which airlines ran best at CMH in August
The three carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airways | 1,073 | 85.2% | 52 min | 1.21% | A |
| Southwest Airlines | 915 | 84.5% | 62 min | 0.55% | B+ |
| Delta Air Lines | 379 | 88.4% | 79 min | 2.11% | A |
| American Airlinesthin sample | 350 | 75.3% | 95 min | 2.29% | B |
| United Airlinesthin sample | 288 | 70.2% | 66 min | 2.08% | C |
| Envoy Airthin sample | 246 | 85.1% | 59 min | 1.22% | A |
| PSA Airlinesthin sample | 196 | 78.6% | 107 min | 2.04% | B |
| Spirit Airlinesthin sample | 150 | 83.8% | 61 min | 0.67% | B+ |
| SkyWest Airlinesthin sample | 66 | 65.1% | 70 min | 4.55% | C− |
| Alaska Airlinesthin sample | 57 | 73.7% | 41 min | 0.00% | C+ |
| Frontier Airlinesthin sample | 38 | 58.3% | 91 min | 5.26% | D− |
No carrier stands out. Delta tops the table at 88.4%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Route by route
Busiest routes out of CMH in August
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| CMH to ORD · Chicago | 407 | 77.1% | 61 min | 3.44% | B− |
| CMH to ATL · Atlantathin sample | 296 | 87.2% | 80 min | 2.03% | A |
| CMH to LGA · New Yorkthin sample | 228 | 84.4% | 51 min | 1.32% | B |
| CMH to DCA · Washingtonthin sample | 180 | 78.7% | 56 min | 1.11% | B |
| CMH to BOS · Bostonthin sample | 175 | 88.4% | 57 min | 1.14% | A |
| CMH to PHL · Philadelphiathin sample | 169 | 77.4% | 84 min | 2.96% | B |
| CMH to CLT · Charlottethin sample | 165 | 84.1% | 140 min | 0.61% | B+ |
| CMH to MCO · Orlandothin sample | 157 | 77.6% | 88 min | 0.64% | B+ |
| CMH to JFK · New Yorkthin sample | 155 | 81.7% | 52 min | 1.29% | B |
| CMH to EWR · Newarkthin sample | 152 | 82.7% | 62 min | 1.32% | B |
| CMH to DEN · Denverthin sample | 148 | 72.8% | 67 min | 0.68% | C+ |
| CMH to DFW · Dallas-Fort Worththin sample | 140 | 74.1% | 103 min | 2.86% | C |
| CMH to DTW · Detroitthin sample | 134 | 92.5% | 29 min | 0.00% | A+ |
| CMH to MDW · Chicagothin sample | 121 | 90.1% | 78 min | 0.00% | A+ |
| CMH to IAD · Washingtonthin sample | 109 | 81.5% | 33 min | 0.92% | B+ |
| CMH to MSP · Minneapolisthin sample | 92 | 83.5% | 66 min | 1.09% | B |
| CMH to BWI · Baltimorethin sample | 92 | 90.0% | 80 min | 2.17% | A |
| CMH to BNA · Nashvillethin sample | 88 | 92.0% | 43 min | 1.14% | A |
| CMH to PHX · Phoenixthin sample | 78 | 81.8% | 85 min | 0.00% | B+ |
| CMH to FLL · Fort Lauderdalethin sample | 69 | 87.0% | 65 min | 0.00% | A+ |
| CMH to LAS · Las Vegasthin sample | 67 | 81.5% | 37 min | 1.49% | B |
| CMH to MIA · Miamithin sample | 66 | 75.4% | 44 min | 0.00% | B+ |
| CMH to TPA · Tampathin sample | 63 | 83.9% | 54 min | 0.00% | B+ |
| CMH to SEA · Seattlethin sample | 57 | 73.7% | 41 min | 0.00% | C+ |
| CMH to STL · St. Louisthin sample | 56 | 90.9% | 95 min | 1.79% | A |
Delay causes
What held CMH up in August
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 45,000 reported delay minutes.
- 38%Late-arriving aircraft
- 34%Carrier
- 28%National Airspace System
- 1%Extreme weather
38% 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 45,000 reported delay minutes here, that single category outweighs weather by 38 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 45,193 reported delay minutes.
Cancellations sit at 1.41% against a national 1.08%, which is ordinary. Diversions add another 0.21%.
6.2% of arrivals land an hour or more late, close to the national 8.2%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
What to do with this
Flying from CMH in August
For a August trip through CMH: expect 82.1% on time and 1.41% cancelled, going by August 2025. The 5am–8am window was the strongest part of the day.
Related
Where to go next
- John Glenn Columbus International (CMH), the whole year
- CMH in July73.3%
- CMH in September85.2%
- CMH in October81.1%
- CMH in November79.9%
- CMH in December70.7%
- CMH in January81.6%
- CMH in February82.9%
- CMH in March76.4%
- CMH in April84.2%
- CMH in May83.4%
- CMH in June81.0%
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.