Carrier route record
WNDEN→LAX
Southwest Airlines · Denver to Los Angeles
- Flights
- 1,918
- 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 DEN to LAX sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 10 points worse than the national rate of 77.6%. The late ones land roughly 50 minutes behind schedule. That rests on 1,918 flights. The strongest carrier on the route with a full sample, United Airlines, flew 3,064 at 84.5% on time.
United Airlines is the most reliable of the four carriers covered here at 84.5% on time across 3,064 flights.
Key figures
On time
68.0%
Arrivals under 15 minutes late, of 1,901 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
0.73%
National rate is 1.81%
Whole route
79.0%
Every carrier on DEN to LAX, 7,721 flights
These figures cover 1,918 flights between July 2025 and June 2026. Beyond the headline rate, 8.0% 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 LAX
Southwest flew 1,918 of the 7,721 flights on DEN to LAX, about 25% of it. Its 68.0% on time is 11 points worse than the route as a whole, which runs 79.0%. Ranked by on-time rate it is last of five carriers on the route, where the range runs from United at 84.5% to Southwest at 68.0%.
The four 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 | 3,064 | 84.5% | 58 min | 0.00% | B+ |
| Frontier Airlines | 762 | 81.1% | 75 min | 0.52% | B+ |
| Delta Air Lines | 746 | 80.5% | 89 min | 1.47% | B |
| SkyWest Airlines | 1,231 | 80.1% | 82 min | 0.81% | B+ |
| Southwest Airlines (this page) | 1,918 | 68.0% | 49 min | 0.73% | C+ |
No carrier stands out. United tops the table at 84.5%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
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 37 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am141 flights89.2%
- 8am–11am487 flights86.6%
- 11am–2pm343 flights70.4%
- 2pm–5pm232 flights59.3%
- 5pm–8pm261 flights53.9%
- 8pm–5am454 flights52.2%
Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 52.2% on time, against 89.2% 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 8am–11am window is the busiest, with 487 flights scheduled in it.
Across the year
Southwest on DEN to LAX through the year
June is the worst month at 43.0% on time, 36 points below January, the best at 78.8%. 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, Wednesday is the strongest day at 74.0% on time and Sunday the weakest at 62.3%. 12 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 55% of the 30,000 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.
- 55%Late-arriving aircraft
- 34%Carrier
- 9%National Airspace System
- 2%Extreme weather
- 0%Security
55% 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 30,000 reported delay minutes here, that single category outweighs weather by 28 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 29,527 reported delay minutes.
The largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 10,000 of the 30,000 delay minutes reported here.
Cancellations are rare at 0.73%, 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
8.0% 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 74.1% on time across 1,917 flights, 6 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 6 points of difference.
The sample behind these figures is 1,918 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 DEN to LAX
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 78.8% on time and June 43.0%, a swing of 36 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
- DEN to LAX, every carrier
- Southwest on LAX to DEN, the return leg
- United Airlines on DEN to LAX84.5%
- Frontier Airlines on DEN to LAX81.1%
- Delta Air Lines on DEN to LAX80.5%
- SkyWest Airlines on DEN to LAX80.1%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- Los Angeles International (LAX) 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.