Carrier route record

UALAS→DEN

United Airlines · Las Vegas to Denver

Flights: 2,416
Period: July 2025 to June 2026
Share of route: 34%
Carriers: 3

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.

United on LAS to DEN lands a B+, 6 points better than the national rate of 77.6%. About one flight in six arrives 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 2,416 flights. The strongest carrier on the route with a full sample, Frontier Airlines, flew 1,554 at 79.1% on time.

Set against the rest of the country, United's LAS to DEN record is 6 points better than the US average of 77.6%. That gap is worth roughly 61 fewer late arrivals for every thousand flights.

On time

83.7%

Arrivals under 15 minutes late, of 2,400 completed flights

Avg delay

68 min

Across delayed arrivals only, not all flights

Cancelled

0.50%

National rate is 1.81%

Whole route

77.0%

Every carrier on LAS to DEN, 7,088 flights

These figures cover 2,416 flights between July 2025 and June 2026. The median arrival is 11 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

United against every carrier on LAS to DEN

United flew 2,416 of the 7,088 flights on LAS to DEN, about 34% of it. Its 83.7% on time is 7 points better than the route as a whole, which runs 77.0%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from United at 83.7% to Southwest at 70.7%.

The choice of carrier is not cosmetic here. Frontier Airlines arrives on time 79.1% of the time; Southwest Airlines manages 70.7%. Sample sizes sit next to every figure, because a two-point gap across 3,118 flights means less than a ten-point one.

On-time performance by carrier on LAS to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines (this page)	2,416	83.7%	68 min	0.50%	B+
Frontier Airlines	1,554	79.1%	90 min	0.97%	B+
Southwest Airlines	3,118	70.7%	57 min	1.12%	C

Frontier leads Southwest by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Flight by flight

United flight numbers on LAS to DEN

Departure window

When United runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 24 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am422 flights96.9%
8am–11am490 flights93.7%
11am–2pm658 flights79.9%
2pm–5pm587 flights74.8%
5pm–8pm257 flights73.2%
8pm–5am2 flights—

Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 96.9% of the time, against 73.2% for the evening 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 658 flights scheduled in it.

Across the year

United on LAS to DEN through the year

Darker means more delays. Figures are on-time percentages.April best, July worst

July is the worst month at 67.3% on time, 28 points below April, the best at 94.8%. 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. October was the busiest month here, with 237 flights.

Across the week, Saturday is the strongest day at 89.2% on time and Friday the weakest at 77.9%. 11 points is a smaller lever than departure hour, but it is free.

Delay causes

Why United 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.

Late-arriving aircraft
42%
National Airspace System
41%
Carrier
15%
Extreme weather
3%

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 15 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 26,377 reported delay minutes.

41% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 11,000 minutes out of 26,000, against a national NAS share of 21%.

Cancellations are rare at 0.50%, 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

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 last about an hour, which a normal layover absorbs.

The 628 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 78.6% on time across 2,420 flights, 5 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 5 points of difference.

The sample behind these figures is 2,416 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 United on LAS to DEN

Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 94.8% on time and July 67.3%, a swing of 28 points. If the dates move at all, move them out of July before you think about anything else. 2,400 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures