Carrier route record
UAMIA→DEN
United Airlines · Miami to Denver
- Flights
- 877
- Period
- September 2025 to August 2026
- Share of route
- 36%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on MIA to DEN lands a B+, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 877 flights, with a median arrival 10 minutes early.
Set against the rest of the country, United's MIA to DEN record is 6 points better than the US average of 77.3%. That gap is worth roughly 57 fewer late arrivals for every thousand flights.
Key figures
On time
83.0%
Arrivals under 15 minutes late, of 871 completed flights
Avg delay
73 min
Across delayed arrivals only, not all flights
Cancelled
0.11%
National rate is 1.89%
Whole route
76.8%
Every carrier on MIA to DEN, 2,444 flights
These figures cover 877 flights between September 2025 and August 2026. The median arrival is 10 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
United against every carrier on MIA to DEN
United flew 877 of the 2,444 flights on MIA to DEN, about 36% of it. Its 83.0% on time is 6 points better than the route as a whole, which runs 76.8%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Frontier at 83.2% to Southwest at 54.5%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 355 | 83.2% | 91 min | 0.85% | B+ |
| United Airlines (this page) | 877 | 83.0% | 73 min | 0.11% | B+ |
| American Airlines | 889 | 76.1% | 58 min | 0.90% | B+ |
| Southwest Airlinesthin sample | 323 | 54.5% | 61 min | 0.00% | F+ |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
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 18 points, against half a point between the best and worst carrier.
- 5am–8am250 flights92.0%
- 8am–11am127 flights92.1%
- 11am–2pm119 flights83.2%
- 2pm–5pm363 flights74.3%
- 5pm–8pm—
- 8pm–5am18 flights—
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 92.1% of the time, against 74.3% for the afternoon window. That is 18 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 363 flights scheduled in it.
Across the year
United on MIA to DEN through the year
August is the worst month at 69.2% on time, 26 points below April, the best at 94.7%. 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. March was the busiest month here, with 113 flights.
Across the week, Wednesday is the strongest day at 89.5% on time and Monday the weakest at 79.7%, a spread of 10 points.
Arrival by arrival
How late United on MIA to DEN runs when it is late
United on MIA to DEN often beats the schedule: 338 of 871 completed flights, 39%, arrived 15 minutes or more early. The 148 late arrivals split 50 under half an hour, 49 between 30 and 60 minutes, and 49 an hour or more.
- 15+ min early338 flights38.8%
- Within 15 min385 flights44.2%
- 15–29 min late50 flights5.7%
- 30–59 min late49 flights5.6%
- 1–2 hours late27 flights3.1%
- 2+ hours late22 flights2.5%
Scale runs 0% to 100%.
Share of 871 completed flights by arrival against schedule.
31 of 142 late departures made up the time and arrived on time, 22% of them. 37 flights left on time and still arrived late.
The worst days
Worst days for United on MIA to DEN
The latest arrival of the period was on 28 March 2026, 7 hours 32 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 28 March 2026 | 7 hours 32 minutes | Late-arriving aircraft |
| 8 November 2025 | 7 hours 2 minutes | Late-arriving aircraft |
| 30 October 2025 | 6 hours 34 minutes | Late-arriving aircraft |
| 19 December 2025 | 6 hours 1 minute | Late-arriving aircraft |
| 10 September 2025 | 5 hours 24 minutes | Carrier |
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 11,000 reported delay minutes.
- 40%Late-arriving aircraft
- 28%National Airspace System
- 27%Carrier
- 5%Extreme weather
- 1%Security
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 9 to one. The split is drawn from 10,849 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 92.1% on time here.
Cancellations are rare at 0.11%, 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 costs
5.6% 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 a little over an hour, which a normal layover absorbs.
At 1,709 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 76.3% on time across 877 flights, 7 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 7 points of difference.
One caution: this is a thin sample. 877 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking United on MIA to DEN
Put together: treat all of this as provisional. 877 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 83.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 871 completed flights over 12 months sit behind that.
Related
Where to go next
- MIA to DEN, every carrier
- United on DEN to MIA, the return leg
- Frontier Airlines on MIA to DEN83.2%
- American Airlines on MIA to DEN76.1%
- Southwest Airlines on MIA to DEN54.5%
- United Airlines network-wide record
- Miami International (MIA) delay statistics
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.