Route reliability record
LAX→DEN
Los Angeles to Denver
- Flights
- 7,709
- Period
- September 2025 to August 2026
- Distance
- 862 mi
- Carriers
- 5
This route lands a B+, 4 points better than the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 7,709 LAX to DEN flights, of which United Airlines flew 3,081 at 87.7% on time.
Best time to fly LAX to DEN: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 93.1% of the time and Tuesday flights 84.4%, against 81.6% for the route overall.
United Airlines is the most reliable of the five carriers covered here at 87.7% on time across 3,081 flights.
Key figures
On time
81.6%
Arrivals under 15 minutes late, of 7,649 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
0.44%
National rate is 1.89%
Best carrier
United
87.7% on time across 3,081 flights
These figures cover 7,709 flights between September 2025 and August 2026. The median arrival is 8 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
Which airline is most reliable on LAX to DEN
The choice of carrier is not cosmetic here. United Airlines arrives on time 87.7% of the time; Southwest Airlines manages 72.2%. Sample sizes sit next to every figure, because a two-point gap across 1,880 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 3,081 | 87.7% | 69 min | 0.00% | A+ |
| SkyWest Airlines | 1,206 | 82.0% | 62 min | 0.75% | B+ |
| Frontier Airlines | 798 | 80.9% | 87 min | 0.75% | B+ |
| Delta Air Lines | 744 | 80.2% | 95 min | 1.34% | B |
| Southwest Airlines | 1,880 | 72.2% | 55 min | 0.48% | C+ |
The spread between United and Southwest is 16 points, wide enough that it should decide the booking. On a hundred trips that is 16 more arrivals inside the on-time window.
Flight by flight
Flights on LAX to DEN
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Los Angeles to Denver
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 4 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. LAX → DENLos Angeles to Denver | United Airlines | 87.7% | 87.7% | 0.00% | 5am–8am, Sun | UA 1912 08:47 |
| 2. BUR → DENBurbank to Denver | United Airlines | 87.3% | 87.5% | 0.24% | 8am–11am, Sat | UA 1191 09:00 |
| 3. ONT → DENOntario to Denver | United Airlines | 86.8% | 87.1% | 0.38% | 5am–8am, Sun | UA 2446 05:00 |
| 4. SNA → DENSanta Ana to Denver | United Airlines | 86.7% | 86.9% | 0.26% | 8am–11am, Sat | UA 2656 18:26 |
| 5. ONT → DENOntario to Denver | Frontier Airlines | 85.9% | 86.5% | 0.72% | 5am–8am, Fri | F9 1500 06:00 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 22 points, against 16 points between the best and worst carrier.
- 5am–8am1,530 flights93.1%
- 8am–11am1,462 flights85.0%
- 11am–2pm1,086 flights83.8%
- 2pm–5pm2,119 flights71.2%
- 5pm–8pm904 flights80.4%
- 8pm–5am608 flights78.9%
Scale runs 65% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.1% of the time, against 71.2% for the afternoon window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 2,119 flights scheduled in it.
Explore
Filter LAX to DEN by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On LAX to DEN, the best departure window is 5am–8am at 93.1% on time and the worst is 2pm–5pm at 71.2%, a wide gap of 21.9 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am93.1%
- 8–11am85.0%
- 11am–2pm83.8%
- 2–5pm71.2%
- 5–8pm80.4%
- 8pm–5am78.9%
best all US flightsScale 60% to 100%.
Across the year
When delays peak on this route
This route's year swings by 17 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.
August is the worst month at 71.4% on time, 17 points below April, the best at 88.7%. 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, Tuesday is the strongest day at 84.4% on time and Monday the weakest at 79.3%, a spread of 5 points.
Delay causes
Why this route gets delayed
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 95,000 reported delay minutes.
- 35%Late-arriving aircraft
- 33%Carrier
- 31%National Airspace System
- 1%Extreme weather
- 0%Security
35% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 95,000 reported delay minutes here, that single category outweighs weather by 26 to one. The split is drawn from 94,856 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 93.1% on time here.
Cancellations are rare at 0.44%, 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 actually costs
6.5% 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 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.
The return leg runs 78.7% on time across 7,708 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 7,709 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.
Work out the risk of missing a connection in DEN after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 88.7% on time and August 71.4%, a swing of 17 points. If the dates move at all, move them out of August before you think about anything else. 7,649 completed flights over 12 months sit behind that.
Common questions
LAX to DEN questions
How often is LAX to DEN delayed?
Roughly one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.4% of the 7,709 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on LAX to DEN?
United Airlines leads at 87.7% on time across 3,081 flights. Southwest Airlines is at the other end on 72.2%, a gap of 16 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 LAX to DEN?
The 5am–8am departure window is the strongest at 93.1% on time. The 2pm–5pm window is the weakest at 71.2%, 22 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 August delays on LAX to DEN?
August is the weakest month at 71.4% on time, compared with 88.7% in April. Across the year that is 17 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
- DEN to LAX — the return legseparate record
- Los Angeles International (LAX) delay statistics
- Denver International (DEN) delay statistics
- United Airlines on LAX to DEN87.7%
- SkyWest Airlines on LAX to DEN82.0%
- Frontier Airlines on LAX to DEN80.9%
- Delta Air Lines on LAX to DEN80.2%
- Southwest Airlines on LAX to DEN72.2%
- LAX to SFO, a related route60.1%
- PHX to DEN, a related route76.7%
- LAX to JFK, a related route77.5%
- United Airlines on-time record87.7%
- SkyWest Airlines on-time record82.0%
- Frontier Airlines on-time record80.9%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. LAX to DEN and DEN to LAX are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.