Carrier route record
UADEN→MIA
United Airlines · Denver to Miami
- 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 DEN to MIA lands a B+, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 877 flights, with a median arrival 5 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate United on DEN to MIA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.3%
Arrivals under 15 minutes late, of 872 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
Whole route
74.9%
Every carrier on DEN to MIA, 2,443 flights
These figures cover 877 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.
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Carrier by carrier
United against every carrier on DEN to MIA
United flew 877 of the 2,443 flights on DEN to MIA, about 36% of it. Its 76.3% on time is about level with the route as a whole at 74.9%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from American at 77.8% to Southwest at 64.5%. 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 |
|---|---|---|---|---|---|
| American Airlines | 890 | 77.8% | 96 min | 1.01% | B |
| United Airlines (this page) | 877 | 76.3% | 60 min | 0.00% | B+ |
| Frontier Airlinesthin sample | 353 | 73.9% | 63 min | 0.28% | C+ |
| Southwest Airlinesthin sample | 323 | 64.5% | 48 min | 0.62% | D+ |
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 is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 877 flights.
- 5am–8am—
- 8am–11am364 flights75.6%
- 11am–2pm35 flights74.3%
- 2pm–5pm324 flights77.4%
- 5pm–8pm99 flights76.8%
- 8pm–5am55 flights74.5%
Scale runs 65% to 85%. Rows with fewer than 30 flights show a dash.
The time of day barely matters here. The 2pm–5pm window tops the set at 77.4% and 11am–2pm sits at 74.3%, 3 points apart across 877 flights. Pick the departure that suits the trip: whatever is going wrong here is not accumulating over the course of the day. The 8am–11am window is the busiest, with 364 flights scheduled in it.
Across the year
United on DEN to MIA through the year
July is the worst month at 55.9% on time, 40 points below April, the best at 96.0%. 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. March was the busiest month here, with 112 flights.
Across the week, Tuesday is the strongest day at 82.8% on time and Saturday the weakest at 68.5%, a spread of 14 points.
Arrival by arrival
How late United on DEN to MIA runs when it is late
United on DEN to MIA often beats the schedule: 276 of 872 completed flights, 32%, arrived 15 minutes or more early. The 207 late arrivals split 75 under half an hour, 64 between 30 and 60 minutes, and 68 an hour or more.
- 15+ min early276 flights31.7%
- Within 15 min389 flights44.6%
- 15–29 min late75 flights8.6%
- 30–59 min late64 flights7.3%
- 1–2 hours late41 flights4.7%
- 2+ hours late27 flights3.1%
Scale runs 0% to 100%.
Share of 872 completed flights by arrival against schedule.
36 of 161 late departures made up the time and arrived on time, 22% of them. In the other direction, 82 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at MIA.
The worst days
Worst days for United on DEN to MIA
The latest arrival of the period was on 16 March 2026, 6 hours 6 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. Three of the five worst days fell in March 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 16 March 2026 | 6 hours 6 minutes | National Airspace System |
| 16 March 2026 | 5 hours 16 minutes | National Airspace System |
| 17 February 2026 | 4 hours 40 minutes | Late-arriving aircraft |
| 29 July 2026 | 4 hours 13 minutes | National Airspace System |
| 13 March 2026 | 4 hours 1 minute | Late-arriving aircraft |
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 12,000 reported delay minutes.
- 40%National Airspace System
- 36%Late-arriving aircraft
- 22%Carrier
- 2%Extreme weather
36% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 12,000 reported delay minutes here, that single category outweighs weather by 18 to one. The split is drawn from 12,458 reported delay minutes.
40% 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 5,041 minutes out of 12,000, against a national NAS share of 21%.
Cancellations are rare at 0.00%, below the national 1.89% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
7.8% 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.
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 83.0% on time across 877 flights, 7 points above 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 DEN to MIA
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 76.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 872 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to MIA, every carrier
- United on MIA to DEN, the return leg
- American Airlines on DEN to MIA77.8%
- Frontier Airlines on DEN to MIA73.9%
- Southwest Airlines on DEN to MIA64.5%
- United Airlines network-wide record
- Denver International (DEN) delay statistics
- Miami International (MIA) delay statistics
- Why the first flight of the morning is statistically safest
- Worst months to fly in the US, ranked by the data
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.