Carrier route record
WNDEN→DTW
Southwest Airlines · Denver to Detroit
- Flights
- 649
- Period
- September 2025 to August 2026
- Share of route
- 21%
- Carriers
- 5
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DEN to DTW earns a D+, which is as low as this site's scale goes for a reason. Only 57.2% of flights arrive inside the 15-minute window, 20 points worse than the national rate of 77.3%. Late arrivals average roughly 50 minutes. Treat any tight connection here as a coin flip. That rests on 649 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,247 at 86.8% on time.
Delta Air Lines is the most reliable of the three carriers covered here at 86.8% on time across 1,247 flights.
Key figures
On time
57.2%
Arrivals under 15 minutes late, of 643 completed flights
Avg delay
52 min
Across delayed arrivals only, not all flights
Cancelled
0.92%
National rate is 1.89%
Whole route
78.1%
Every carrier on DEN to DTW, 3,109 flights
These figures cover 649 flights between September 2025 and August 2026. Beyond the headline rate, 12.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Southwest against every carrier on DEN to DTW
Southwest flew 649 of the 3,109 flights on DEN to DTW, about 21% of it. Its 57.2% on time is 21 points worse than the route as a whole, which runs 78.1%. Ranked by on-time rate it is last of five carriers on the route, where the range runs from SkyWest at 100.0% to Southwest at 57.2%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 86.8% of the time; Frontier Airlines manages 79.6%. Sample sizes sit next to every figure, because a two-point gap across 486 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Delta Air Lines | 1,247 | 86.8% | 79 min | 0.32% | A+ |
| United Airlines | 726 | 80.5% | 63 min | 0.14% | B+ |
| Frontier Airlines | 486 | 79.6% | 83 min | 1.23% | B |
| Southwest Airlines (this page) | 649 | 57.2% | 52 min | 0.92% | D+ |
Delta leads Frontier by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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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 26 points, against 7 points between the best and worst carrier.
- 5am–8am—
- 8am–11am106 flights69.8%
- 11am–2pm201 flights68.5%
- 2pm–5pm30 flights56.7%
- 5pm–8pm292 flights43.9%
- 8pm–5am20 flights—
Scale runs 35% to 75%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 43.9% on time, against 69.8% for the 8am–11am 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 292 flights scheduled in it.
Across the year
Southwest on DEN to DTW through the year
November is the best month on the calendar at 77.3% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 62 flights.
Across the week, Saturday is the strongest day at 64.9% on time and Monday the weakest at 45.9%, a spread of 19 points.
Arrival by arrival
How late Southwest on DEN to DTW runs when it is late
The 275 late arrivals split 106 under half an hour, 92 between 30 and 60 minutes, and 77 an hour or more.
- 15+ min early40 flights6.2%
- Within 15 min328 flights51.0%
- 15–29 min late106 flights16.5%
- 30–59 min late92 flights14.3%
- 1–2 hours late55 flights8.6%
- 2+ hours late22 flights3.4%
Scale runs 0% to 100%.
Share of 643 completed flights by arrival against schedule.
73 of 315 late departures made up the time and arrived on time, 23% of them. In the other direction, 33 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at DTW.
The worst days
Worst days for Southwest on DEN to DTW
The latest arrival of the period was on 29 July 2026, 5 hours 16 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. Three of the five worst days fell in August 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 29 July 2026 | 5 hours 16 minutes | Late-arriving aircraft |
| 3 August 2026 | 4 hours 49 minutes | Late-arriving aircraft |
| 23 August 2026 | 4 hours 31 minutes | Carrier |
| 21 August 2026 | 4 hours 10 minutes | Late-arriving aircraft |
| 1 December 2025 | 3 hours 34 minutes | Late-arriving aircraft |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 61% of the 14,000 delay minutes carriers reported here, and the remaining four split what is left.
- 61%Late-arriving aircraft
- 30%Carrier
- 9%National Airspace System
- 0%Security
61% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 14,000 reported delay minutes here, that single category outweighs weather by 61 to one. The split is drawn from 14,393 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 69.8% on time here.
Cancellations sit at 0.92% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
12.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 1,123 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 73.9% on time across 649 flights, 17 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 17 points of difference.
One caution: this is a thin sample. 649 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 DTW
Put together: treat all of this as provisional. 649 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 57.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 643 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to DTW, every carrier
- Southwest on DTW to DEN, the return leg
- Delta Air Lines on DEN to DTW86.8%
- United Airlines on DEN to DTW80.5%
- Frontier Airlines on DEN to DTW79.6%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- Detroit Metropolitan Wayne County (DTW) 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.