Carrier performance at one airport

UA→DEN

United Airlines at Denver International

Departures: 107,305
Period: July 2025 to June 2026
Routes: 25
Rank here: #3 of 9

United Airlines at Denver 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 107,305 flights, of which Delta Air Lines flew 11,579 at 83.1% on time.

Measured against the airport rather than the country, United Airlines runs 2 points ahead of the 76.3% 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

78.4%

106,528 completed departures

Avg delay

64 min

Across delayed flights only

Cancelled

0.46%

At DEN, this carrier only

Rank here

Of 9 carriers clearing the floor at DEN

These figures cover 107,000 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.

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 68.9%. Sample sizes sit next to every figure, because a two-point gap across 1,249 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	11,579	83.1%	77 min	1.33%	B
SkyWest Airlines	75,349	80.0%	77 min	1.13%	B
United Airlines (this page)	107,305	78.4%	64 min	0.46%	B+
Frontier Airlines	22,581	78.0%	67 min	0.73%	B+
American Airlines	8,874	76.8%	104 min	2.12%	B
Alaska Airlines	2,700	76.0%	56 min	0.89%	B+
Allegiant Air	395	70.3%	110 min	1.27%	C
Southwest Airlines	88,768	69.4%	54 min	0.70%	C+
JetBlue Airways	1,249	68.9%	89 min	2.80%	C

The spread between Delta and JetBlue is 14 points, wide enough that it should decide the booking. On a hundred trips that is 14 more arrivals inside the on-time window.

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	3,875	78.0%	62 min	0.23%	B+
DEN to ORD · Chicago	3,756	71.4%	79 min	0.75%	C+
DEN to SFO · San Francisco	3,373	71.2%	63 min	0.42%	C+
DEN to EWR · Newark	3,363	77.5%	80 min	1.58%	B
DEN to LAX · Los Angeles	3,064	84.5%	58 min	0.00%	B+
DEN to IAD · Washington	2,797	84.4%	70 min	0.46%	B+
DEN to LAS · Las Vegas	2,420	78.6%	66 min	0.37%	B+
DEN to PHX · Phoenix	2,369	80.5%	63 min	0.34%	B+
DEN to SAN · San Diego	2,081	79.8%	59 min	0.48%	B+
DEN to LGA · New York	2,017	74.0%	69 min	1.83%	C
DEN to AUS · Austin	1,914	79.9%	64 min	0.63%	B+
DEN to BOS · Boston	1,911	77.1%	70 min	0.84%	B+
DEN to SEA · Seattle	1,903	80.0%	55 min	0.63%	B+
DEN to DFW · Dallas-Fort Worth	1,902	77.2%	69 min	0.79%	B+
DEN to SNA · Santa Ana	1,870	84.8%	49 min	0.32%	B+
DEN to PDX · Portland	1,821	81.7%	60 min	0.44%	B+
DEN to SMF · Sacramento	1,797	80.6%	62 min	0.33%	B+
DEN to MCO · Orlando	1,762	82.2%	76 min	0.40%	B+
DEN to MSP · Minneapolis	1,457	79.9%	68 min	0.34%	B+
DEN to RNO · Reno	1,345	76.5%	69 min	0.22%	B+
DEN to SLC · Salt Lake City	1,331	77.5%	58 min	0.15%	B+
DEN to MCI · Kansas City	1,297	78.2%	66 min	0.39%	B+
DEN to OMA · Omaha	1,287	76.5%	64 min	0.31%	B+
DEN to FLL · Fort Lauderdale	1,225	81.2%	58 min	0.33%	B+
DEN to SAT · San Antonio	1,205	81.9%	63 min	0.25%	B+

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 14 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am5,434 flights91.1%
8am–11am21,825 flights85.7%
11am–2pm26,205 flights81.6%
2pm–5pm12,977 flights76.0%
5pm–8pm33,354 flights71.1%
8pm–5am7,510 flights74.0%

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 91.1% of the time, against 71.1% 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 33,354 flights scheduled in it.

Across the year

Seasonal pattern

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

July is the worst month at 62.4% on time, 25 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. June was the busiest month here, with 9,694 flights.

Delay causes

What holds this operation up

Late-arriving aircraft
46%
Carrier
27%
National Airspace System
25%
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. That is a cascade, and cascades start small and grow through the day. Across 1.48 million reported delay minutes here, that single category outweighs weather by 18 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 1,476,258 reported delay minutes.

Cancellations are rare at 0.46%, 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.

7.4% 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.

107,305 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 July 62.4%, a swing of 25 points. If the dates move at all, move them out of July before you think about anything else. 106,528 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 arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.6% of the 107,305 flights in this analysis, against 22.4% 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 11,579 flights. JetBlue Airways is at the other end on 68.9%, a gap of 14 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 91.1% on time. The 5pm–8pm window is the weakest at 71.1%, 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 July delays on United Airlines at DEN?

July is the weakest month at 62.4% on time, compared with 87.0% in April. Across the year that is 25 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, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures