Route reliability record
DEN→LAX
Denver to Los Angeles
- Flights
- 7,721
- Period
- July 2025 to June 2026
- Distance
- 862 mi
- Carriers
- 5
This route lands a B+, about a point better than the national rate of 77.6%. About one flight in five arrive 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 7,721 flights, of which United Airlines flew 3,064 at 84.5% on time.
United Airlines is the most reliable of the five carriers covered here at 84.5% on time across 3,064 flights.
Key figures
On time
79.0%
Arrivals under 15 minutes late, of 7,676 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
0.51%
National rate is 1.81%
Best carrier
United
84.5% on time across 3,064 flights
These figures cover 7,721 flights between July 2025 and June 2026. The median arrival is 5 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
Which airline is most reliable on DEN to LAX
The choice of carrier is not cosmetic here. United Airlines arrives on time 84.5% of the time; Southwest Airlines manages 68.0%. Sample sizes sit next to every figure, because a two-point gap across 1,918 flights means less than a ten-point one.
| 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 | 1,918 | 68.0% | 49 min | 0.73% | C+ |
The spread between United and Southwest is 17 points, wide enough that it should decide the booking. On a hundred trips that is 17 more arrivals inside the on-time window.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 24 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1,004 flights90.6%
- 8am–11am1,250 flights89.1%
- 11am–2pm1,819 flights84.1%
- 2pm–5pm716 flights75.7%
- 5pm–8pm1,555 flights70.1%
- 8pm–5am1,377 flights66.5%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.6% of the time, against 66.5% for the overnight window. That is 24 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 1,819 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 18 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 66.5% on time, 18 points below November, the best at 84.7%. 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. May was the busiest month here, with 687 flights.
Across the week, Wednesday is the strongest day at 82.8% on time and Sunday the weakest at 75.7%. 7 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 42% of the 100,000 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.
- 42%Late-arriving aircraft
- 41%Carrier
- 14%National Airspace System
- 3%Extreme weather
- 0%Security
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 100,000 reported delay minutes here, that single category outweighs weather by 14 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 100,283 reported delay minutes.
The largest share of delay minutes, 41%, 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 41,000 of the 100,000 delay minutes reported here.
Cancellations are rare at 0.51%, 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 actually costs
6.6% 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 are the about an hour kind, 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 runs 81.7% on time across 7,721 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 7,721 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 this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 84.7% on time and June 66.5%, a swing of 18 points. If the dates move at all, move them out of June before you think about anything else. 7,676 completed flights over 12 months sit behind that.
Common questions
DEN to LAX questions
How often is DEN to LAX delayed?
About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.0% of the 7,721 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on DEN to LAX?
United Airlines leads at 84.5% on time across 3,064 flights. Southwest Airlines is at the other end on 68.0%, a gap of 17 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on DEN to LAX?
The 5am–8am departure window is the strongest at 90.6% on time. The 8pm–5am window is the weakest at 66.5%, 24 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are June delays on DEN to LAX?
June is the weakest month at 66.5% on time, compared with 84.7% in November. Across the year that is 18 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- LAX to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- Los Angeles International (LAX) delay statistics
- United Airlines on-time record84.5%
- Frontier Airlines on-time record81.1%
- Delta Air Lines on-time record80.5%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. DEN to LAX and LAX to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.