Route reliability record
DEN→CMH
Denver to Columbus
- Flights
- 1,767
- Period
- July 2025 to June 2026
- Distance
- 1,154 mi
- Carriers
- 3
This route sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 1,767 DEN to CMH flights, of which United Airlines flew 729 at 81.4% on time.
Best time to fly DEN to CMH: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 83.9% of the time and Tuesday flights 77.6%, against 72.7% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 5 points behind the country as a whole. Across a thousand flights that is about 49 extra late arrivals.
Key figures
On time
72.7%
Arrivals under 15 minutes late, of 1,749 completed flights
Avg delay
55 min
Across delayed arrivals only, not all flights
Cancelled
0.74%
National rate is 1.81%
Best carrier
United
81.4% on time across 729 flights
These figures cover 1,767 flights between July 2025 and June 2026. Beyond the headline rate, 8.3% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on DEN to CMH
The choice of carrier is not cosmetic here. United Airlines arrives on time 81.4% of the time; Southwest Airlines manages 64.7%. Sample sizes sit next to every figure, because a two-point gap across 921 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 729 | 81.4% | 55 min | 0.69% | B+ |
| Frontier Airlinesthin sample | 117 | 81.0% | 100 min | 0.85% | B+ |
| Southwest Airlines | 921 | 64.7% | 53 min | 0.76% | D+ |
The spread between United and Southwest is 17 points, wide enough that it should decide the booking. On a hundred trips that is 17 more arrivals inside the on-time window.
Best ways to make this trip
The most reliable ways to fly Denver to Columbus
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. DEN → CMHDenver to Columbus | United Airlines | 80.8% | 81.4% | 0.69% | 8am–11am, Tue | — |
| 2. DEN → CMHDenver to Columbus | Southwest Airlines | 64.2% | 64.7% | 0.76% | 5am–8am, Tue | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 20 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am30 flights80.0%
- 8am–11am611 flights83.9%
- 11am–2pm170 flights78.1%
- 2pm–5pm284 flights63.5%
- 5pm–8pm649 flights64.5%
- 8pm–5am23 flights—
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 83.9% of the time, against 63.5% for the afternoon window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 649 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 29 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 56.5% on time, 29 points below November, the best at 85.0%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. October was the busiest month here, with 166 flights.
Across the week, Tuesday is the strongest day at 77.6% on time and Wednesday the weakest at 69.5%. 8 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 50% of the 26,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 50%Late-arriving aircraft
- 32%Carrier
- 16%National Airspace System
- 1%Extreme weather
- 0%Security
50% 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 26,000 reported delay minutes here, that single category outweighs weather by 47 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 26,454 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 83.9% on time here.
Cancellations are rare at 0.74%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
8.3% of arrivals land an hour or more late, close to the national 8.1%. 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 about an hour, which a normal layover absorbs.
The 1,154 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 79.2% on time across 1,768 flights, 7 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 7 points of difference.
The sample behind these figures is 1,767 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in CMH after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 85.0% on time and July 56.5%, a swing of 29 points. If the dates move at all, move them out of July before you think about anything else. 1,749 completed flights over 12 months sit behind that.
Common questions
DEN to CMH questions
How often is DEN to CMH delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 27.3% of the 1,767 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on DEN to CMH?
United Airlines leads at 81.4% on time across 729 flights. Southwest Airlines is at the other end on 64.7%, a gap of 17 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on DEN to CMH?
The 8am–11am departure window is the strongest at 83.9% on time. The 2pm–5pm window is the weakest at 63.5%, 20 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are July delays on DEN to CMH?
July is the weakest month at 56.5% on time, compared with 85.0% in November. Across the year that is 29 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- CMH to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- John Glenn Columbus International (CMH) delay statistics
- United Airlines on DEN to CMH81.4%
- Frontier Airlines on DEN to CMH81.0%
- Southwest Airlines on DEN to CMH64.7%
- DEN to PHX, a related route75.7%
- ORD to CMH, a related route73.1%
- DEN to SLC, a related route77.5%
- United Airlines on-time record81.4%
- Frontier Airlines on-time record81.0%
- Southwest Airlines on-time record64.7%
- Why the first flight of the morning is statistically safest
- Same route, different airline: where the carrier you pick matters most
Direction matters. DEN to CMH and CMH to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.