Carrier route record
WNDEN→CMH
Southwest Airlines · Denver to Columbus
- Flights
- 921
- Period
- July 2025 to June 2026
- Share of route
- 52%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DEN to CMH draws a D+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is roughly 55 minutes behind schedule. Build slack into anything you connect to. That rests on 921 flights, with a median arrival 5 minutes late.
The national on-time rate over the same period is 77.6%, so Southwest on DEN to CMH runs 13 points behind the country as a whole. Across a thousand flights that is about 129 extra late arrivals.
Key figures
On time
64.7%
Arrivals under 15 minutes late, of 911 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
0.76%
National rate is 1.81%
Whole route
72.7%
Every carrier on DEN to CMH, 1,767 flights
These figures cover 921 flights between July 2025 and June 2026. Beyond the headline rate, 10.6% 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
Southwest against every carrier on DEN to CMH
Southwest flew 921 of the 1,767 flights on DEN to CMH, most of the route. Its 64.7% on time is 8 points worse than the route as a whole, which runs 72.7%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from United at 81.4% to Southwest at 64.7%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| 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 (this page) | 921 | 64.7% | 53 min | 0.76% | D+ |
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 28 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am30 flights80.0%
- 8am–11am245 flights76.5%
- 11am–2pm118 flights76.1%
- 2pm–5pm220 flights58.9%
- 5pm–8pm285 flights52.1%
- 8pm–5am23 flights—
Scale runs 45% to 85%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 52.1% on time, against 80.0% 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 5pm–8pm window is the busiest, with 285 flights scheduled in it.
Across the year
Southwest on DEN to CMH through the year
June is the worst month at 44.0% on time, 42 points below January, the best at 85.5%. 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. July was the busiest month here, with 91 flights.
Across the week, Tuesday is the strongest day at 69.9% on time and Sunday the weakest at 60.4%. 10 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 54% of the 17,000 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.
- 54%Late-arriving aircraft
- 30%Carrier
- 14%National Airspace System
- 1%Extreme weather
- 0%Security
54% 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 17,000 reported delay minutes here, that single category outweighs weather by 54 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 16,937 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 80.0% on time here.
Cancellations are rare at 0.76%, 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 costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.6% of arrivals land a full hour or more behind schedule, against 8.1% 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.
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 78.4% on time across 922 flights, 14 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 14 points of difference.
One caution: this is a thin sample. 921 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Southwest on DEN to CMH
Put together: treat all of this as provisional. 921 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 64.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 911 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to CMH, every carrier
- Southwest on CMH to DEN, the return leg
- United Airlines on DEN to CMH81.4%
- Frontier Airlines on DEN to CMH81.0%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- John Glenn Columbus International (CMH) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
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.