Carrier route record
WNCLE→DEN
Southwest Airlines · Cleveland to Denver
- Flights
- 609
- Period
- September 2025 to August 2026
- Share of route
- 33%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on CLE to DEN lands a B+, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 609 flights, with a median arrival 4 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate Southwest on CLE to DEN from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.9%
Arrivals under 15 minutes late, of 601 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
0.66%
National rate is 1.89%
Whole route
82.4%
Every carrier on CLE to DEN, 1,845 flights
These figures cover 609 flights between September 2025 and August 2026. The median arrival is 4 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.
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Carrier by carrier
Southwest against every carrier on CLE to DEN
Southwest flew 609 of the 1,845 flights on CLE to DEN, about 33% of it. Its 76.9% on time is 6 points worse than the route as a whole, which runs 82.4%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from United at 87.5% to Southwest at 76.9%. 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 | 940 | 87.5% | 69 min | 0.11% | A+ |
| Frontier Airlinesthin sample | 296 | 77.3% | 59 min | 1.69% | B |
| Southwest Airlines (this page) | 609 | 76.9% | 60 min | 0.66% | B+ |
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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 44 points, against half a point between the best and worst carrier.
- 5am–8am276 flights95.2%
- 8am–11am7 flights—
- 11am–2pm52 flights82.7%
- 2pm–5pm47 flights76.6%
- 5pm–8pm215 flights51.0%
- 8pm–5am12 flights—
Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 51.0% on time, against 95.2% 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 276 flights scheduled in it.
Across the year
Southwest on CLE to DEN through the year
August is the worst month at 61.7% on time, 25 points below November, the best at 86.7%. 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 62 flights.
Across the week, Saturday is the strongest day at 81.4% on time and Monday the weakest at 70.2%, a spread of 11 points.
Arrival by arrival
How late Southwest on CLE to DEN runs when it is late
The 139 late arrivals split 54 under half an hour, 39 between 30 and 60 minutes, and 46 an hour or more.
- 15+ min early122 flights20.3%
- Within 15 min340 flights56.6%
- 15–29 min late54 flights9.0%
- 30–59 min late39 flights6.5%
- 1–2 hours late31 flights5.2%
- 2+ hours late15 flights2.5%
Scale runs 0% to 100%.
Share of 601 completed flights by arrival against schedule.
30 of 141 late departures made up the time and arrived on time, 21% of them. 28 flights left on time and still arrived late.
The worst days
Worst days for Southwest on CLE to DEN
The latest arrival of the period was on 14 August 2026, 4 hours 57 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The five worst days are spread across August, June, April and March, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 14 August 2026 | 4 hours 57 minutes | National Airspace System |
| 10 June 2026 | 4 hours 40 minutes | National Airspace System |
| 11 August 2026 | 4 hours 40 minutes | Carrier |
| 24 April 2026 | 4 hours 23 minutes | Late-arriving aircraft |
| 31 March 2026 | 3 hours 44 minutes | Extreme weather |
Delay causes
Why Southwest runs late on this route
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 8,346 reported delay minutes.
- 40%Late-arriving aircraft
- 36%National Airspace System
- 19%Carrier
- 4%Extreme weather
- 1%Security
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 8,346 reported delay minutes here, that single category outweighs weather by 10 to one. The split is drawn from 8,346 reported delay minutes.
36% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,043 minutes out of 8,346, against a national NAS share of 21%.
Cancellations are rare at 0.66%, below the national 1.89% 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
7.7% of arrivals land an hour or more late, close to the national 8.3%, so 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 1,201 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.
The return leg is a different operation and performs like one: it runs 61.4% on time across 610 flights, 16 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 16 points of difference.
One caution: this is a thin sample. 609 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 CLE to DEN
Put together: treat all of this as provisional. 609 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 76.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 601 completed flights over 12 months sit behind that.
Related
Where to go next
- CLE to DEN, every carrier
- Southwest on DEN to CLE, the return leg
- United Airlines on CLE to DEN87.5%
- Frontier Airlines on CLE to DEN77.3%
- Southwest Airlines network-wide record
- Cleveland Hopkins International (CLE) delay statistics
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.