Carrier route record
WNLAX→DEN
Southwest Airlines · Los Angeles to Denver
- Flights
- 1,917
- Period
- July 2025 to June 2026
- Share of route
- 25%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on LAX to DEN sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land roughly 50 minutes behind schedule. That rests on 1,917 flights. The strongest carrier on the route with a full sample, United Airlines, flew 3,067 at 87.1% on time.
United Airlines is the most reliable of the four carriers covered here at 87.1% on time across 3,067 flights.
Key figures
On time
74.1%
Arrivals under 15 minutes late, of 1,901 completed flights
Avg delay
52 min
Across delayed arrivals only, not all flights
Cancelled
0.47%
National rate is 1.81%
Whole route
81.7%
Every carrier on LAX to DEN, 7,721 flights
These figures cover 1,917 flights between July 2025 and June 2026. The median arrival is 2 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
Southwest against every carrier on LAX to DEN
Southwest flew 1,917 of the 7,721 flights on LAX to DEN, about 25% of it. Its 74.1% on time is 8 points worse than the route as a whole, which runs 81.7%. Ranked by on-time rate it is last of five carriers on the route, where the range runs from United at 87.1% to Southwest at 74.1%.
The choice of carrier is not cosmetic here. United Airlines arrives on time 87.1% of the time; Delta Air Lines manages 79.7%. Sample sizes sit next to every figure, because a two-point gap across 744 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 3,067 | 87.1% | 68 min | 0.10% | A+ |
| Frontier Airlines | 762 | 81.9% | 90 min | 0.79% | B+ |
| SkyWest Airlines | 1,231 | 81.2% | 61 min | 0.81% | B+ |
| Delta Air Lines | 744 | 79.7% | 85 min | 1.48% | B |
| Southwest Airlines (this page) | 1,917 | 74.1% | 52 min | 0.47% | C+ |
United leads Delta by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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 36 points, against 7 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am369 flights95.6%
- 8am–11am478 flights79.4%
- 11am–2pm302 flights72.3%
- 2pm–5pm450 flights60.0%
- 5pm–8pm224 flights61.0%
- 8pm–5am94 flights67.7%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 95.6% of the time, against 60.0% for the afternoon window. That is 36 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 478 flights scheduled in it.
Across the year
Southwest on LAX to DEN through the year
June is the worst month at 58.1% on time, 26 points below April, the best at 84.3%. 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 180 flights.
Across the week, Tuesday is the strongest day at 79.7% on time and Friday the weakest at 70.4%. 9 points is a smaller lever than departure hour, but it is free.
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 26,000 reported delay minutes.
- 42%Late-arriving aircraft
- 31%National Airspace System
- 27%Carrier
- 1%Extreme weather
42% 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 37 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 25,723 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 95.6% on time here.
Cancellations are rare at 0.47%, 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
7.0% 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 roughly 50 minutes, which a normal layover absorbs.
The 862 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 68.0% on time across 1,918 flights, 6 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 6 points of difference.
The sample behind these figures is 1,917 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.
What to do with this
Booking Southwest on LAX to DEN
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 84.3% on time and June 58.1%, a swing of 26 points. If the dates move at all, move them out of June before you think about anything else. 1,901 completed flights over 12 months sit behind that.
Related
Where to go next
- LAX to DEN, every carrier
- Southwest on DEN to LAX, the return leg
- United Airlines on LAX to DEN87.1%
- Frontier Airlines on LAX to DEN81.9%
- SkyWest Airlines on LAX to DEN81.2%
- Delta Air Lines on LAX to DEN79.7%
- Southwest Airlines network-wide record
- Los Angeles International (LAX) 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 7.04 million flight records
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.