Route reliability record
CMH→DEN
Columbus to Denver
- Flights
- 1,768
- Period
- July 2025 to June 2026
- Distance
- 1,154 mi
- Carriers
- 3
This route lands a B+, 2 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 1,768 CMH to DEN flights, of which United Airlines flew 729 at 81.9% on time.
Best time to fly CMH to DEN: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 93.9% of the time and Wednesday flights 85.3%, against 79.2% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
79.2%
Arrivals under 15 minutes late, of 1,746 completed flights
Avg delay
67 min
Across delayed arrivals only, not all flights
Cancelled
0.68%
National rate is 1.81%
Best carrier
United
81.9% on time across 729 flights
These figures cover 1,768 flights between July 2025 and June 2026. The median arrival is 5 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
Which airline is most reliable on CMH to DEN
The two 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 |
|---|---|---|---|---|---|
| United Airlines | 729 | 81.9% | 72 min | 0.82% | B+ |
| Southwest Airlines | 922 | 78.4% | 62 min | 0.54% | B+ |
| Frontier Airlinesthin sample | 117 | 69.0% | 81 min | 0.85% | C+ |
No carrier stands out. United tops the table at 81.9%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on CMH to DEN
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Best ways to make this trip
The most reliable ways to fly Columbus to Denver
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. CMH → DENColumbus to Denver | United Airlines | 81.2% | 81.9% | 0.82% | 8am–11am, Wed | UA 728 08:55 |
| 2. CMH → DENColumbus to Denver | Southwest Airlines | 78.0% | 78.4% | 0.54% | 5am–8am, Wed | — |
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 29 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am348 flights93.9%
- 8am–11am387 flights85.6%
- 11am–2pm109 flights79.6%
- 2pm–5pm431 flights76.2%
- 5pm–8pm368 flights65.1%
- 8pm–5am125 flights70.2%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.9% of the time, against 65.1% for the evening window. That is 29 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 431 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 27 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.
December is the weak month at 63.1% on time, against 89.9% in April. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. October was the busiest month here, with 166 flights.
Across the week, Wednesday is the strongest day at 85.3% on time and Sunday the weakest at 76.2%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
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 24,000 reported delay minutes.
- 39%Late-arriving aircraft
- 29%National Airspace System
- 29%Carrier
- 3%Extreme weather
- 0%Security
39% 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 24,000 reported delay minutes here, that single category outweighs weather by 13 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 24,378 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 93.9% on time here.
Cancellations are rare at 0.68%, 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
6.8% 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 72.7% on time across 1,767 flights, 7 points below 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 1,768 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 DEN 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. April runs 89.9% on time and December 63.1%, a swing of 27 points. If the dates move at all, move them out of December before you think about anything else. 1,746 completed flights over 12 months sit behind that.
Common questions
CMH to DEN questions
How often is CMH to DEN delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.8% of the 1,768 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on CMH to DEN?
United Airlines leads at 81.9% on time across 729 flights. Southwest Airlines is at the other end on 78.4%, a gap of 4 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 CMH to DEN?
The 5am–8am departure window is the strongest at 93.9% on time. The 5pm–8pm window is the weakest at 65.1%, 29 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 December delays on CMH to DEN?
December is the weakest month at 63.1% on time, compared with 89.9% in April. Across the year that is 27 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
- DEN to CMH — the return legseparate record
- John Glenn Columbus International (CMH) delay statistics
- Denver International (DEN) delay statistics
- United Airlines on CMH to DEN81.9%
- Southwest Airlines on CMH to DEN78.4%
- Frontier Airlines on CMH to DEN69.0%
- CMH to ORD, a related route74.5%
- PHX to DEN, a related route77.2%
- CMH to ATL, a related route85.9%
- United Airlines on-time record81.9%
- Southwest Airlines on-time record78.4%
- Frontier Airlines on-time record69.0%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. CMH to DEN and DEN to CMH 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.