Carrier performance at one airport

UA→DEN

United Airlines at Denver International

Departures: 107,895
Period: September 2025 to August 2026
Routes: 25
Rank here: #3 of 9

United Airlines at Denver lands a B+, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 107,895 flights, of which Delta Air Lines flew 11,497 at 83.1% on time.

Measured against the airport rather than the country, United Airlines runs 2 points ahead of the 76.7% weighted average across all carriers at DEN. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.

On time

78.9%

107,125 completed departures

Avg delay

65 min

Across delayed flights only

Cancelled

0.41%

At DEN, this carrier only

Rank here

Of 9 carriers clearing the floor at DEN

These figures cover 108,000 flights between September 2025 and August 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.

Against the competition

Every carrier at DEN, ranked

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 83.1% of the time; JetBlue Airways manages 65.7%. Sample sizes sit next to every figure, because a two-point gap across 1,258 flights means less than a ten-point one.

On-time performance of all carriers departing DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	11,497	83.1%	75 min	1.37%	B
SkyWest Airlines	75,223	80.4%	78 min	1.09%	B
United Airlines (this page)	107,895	78.9%	65 min	0.41%	B+
Frontier Airlines	22,870	78.5%	68 min	0.77%	B+
Alaska Airlines	2,879	78.1%	57 min	0.66%	B+
American Airlines	8,936	77.1%	105 min	1.97%	B
Allegiant Air	373	76.5%	94 min	0.54%	B+
Southwest Airlines	88,424	69.5%	54 min	0.72%	C+
JetBlue Airways	1,258	65.7%	93 min	4.61%	C−

JetBlue Airways cancels 4.6% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

Route by route

Where United Airlines flies from DEN

United Airlines operates 25 routes out of DEN with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.

United Airlines routes from DEN
Route	Flights	On time	Avg delay	Cancelled	Grade
DEN to IAH · Houston	3,894	79.7%	63 min	0.26%	B+
DEN to ORD · Chicago	3,885	71.9%	82 min	0.82%	C+
DEN to SFO · San Francisco	3,429	69.0%	63 min	0.23%	C+
DEN to EWR · Newark	3,344	78.8%	83 min	1.53%	B
DEN to LAX · Los Angeles	3,079	84.0%	56 min	0.00%	B+
DEN to IAD · Washington	2,790	84.8%	66 min	0.50%	B+
DEN to LAS · Las Vegas	2,401	79.4%	65 min	0.33%	B+
DEN to PHX · Phoenix	2,390	81.6%	64 min	0.25%	B+
DEN to SAN · San Diego	2,067	77.9%	59 min	0.34%	B+
DEN to LGA · New York	2,021	73.5%	74 min	1.78%	C
DEN to SEA · Seattle	1,908	80.9%	57 min	0.47%	B+
DEN to SNA · Santa Ana	1,901	85.3%	48 min	0.16%	A+
DEN to BOS · Boston	1,887	76.8%	75 min	0.95%	B+
DEN to AUS · Austin	1,883	79.6%	61 min	0.32%	B+
DEN to DFW · Dallas-Fort Worth	1,878	77.5%	68 min	0.59%	B+
DEN to PDX · Portland	1,822	82.3%	59 min	0.38%	B+
DEN to SMF · Sacramento	1,791	80.5%	62 min	0.11%	B+
DEN to MCO · Orlando	1,713	82.7%	77 min	0.35%	B+
DEN to MSP · Minneapolis	1,482	80.4%	68 min	0.27%	B+
DEN to SLC · Salt Lake City	1,316	79.0%	57 min	0.15%	B+
DEN to MCI · Kansas City	1,296	79.5%	70 min	0.31%	B+
DEN to RNO · Reno	1,292	77.2%	66 min	0.15%	B+
DEN to OMA · Omaha	1,285	78.1%	67 min	0.23%	B+
DEN to BZN · Bozeman	1,210	83.1%	58 min	0.17%	B+
DEN to SAT · San Antonio	1,196	83.6%	72 min	0.17%	B+

Flight by flight

United Airlines flight numbers from DEN

171 United Airlines flight numbers leaving DEN flew their main route often enough to have a record of their own. Grouped by destination.

Departure window

Best time of day for this operation

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 20 points, against 17 points between the best and worst carrier.

5am–8am5,599 flights91.3%
8am–11am21,938 flights86.3%
11am–2pm26,658 flights82.0%
2pm–5pm13,001 flights76.1%
5pm–8pm33,778 flights71.4%
8pm–5am6,921 flights74.5%

Scale runs 65% to 95%.

Book the early departure. Flights leaving between 5am–8am arrive on time 91.3% of the time, against 71.4% for the evening window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 33,778 flights scheduled in it.

Across the year

Seasonal pattern

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

August is the worst month at 68.7% on time, 18 points below April, the best at 87.0%. 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 9,851 flights.

Delay causes

What holds this operation up

Late-arriving aircraft
46%
National Airspace System
26%
Carrier
26%
Extreme weather
2%
Security
0%

46% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 1.47 million reported delay minutes here, that single category outweighs weather by 22 to one. The split is drawn from 1,471,863 reported delay minutes.

Cancellations are rare at 0.41%, 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.

7.3% 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.

107,895 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.

Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 87.0% on time and August 68.7%, a swing of 18 points. If the dates move at all, move them out of August before you think about anything else. 107,125 completed flights over 12 months sit behind that.

Common questions

United Airlines at DEN

How often is United Airlines at DEN delayed?

About 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 21.1% of the 107,895 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on United Airlines at DEN?

Delta Air Lines leads at 83.1% on time across 11,497 flights. JetBlue Airways is at the other end on 65.7%, 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 United Airlines at DEN?

The 5am–8am departure window is the strongest at 91.3% on time. The 5pm–8pm window is the weakest at 71.4%, 20 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 United Airlines at DEN?

August is the weakest month at 68.7% on time, compared with 87.0% in April. 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.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures