Route reliability record
DEN→MIA
Denver to Miami
- Flights
- 2,443
- Period
- September 2025 to August 2026
- Distance
- 1,709 mi
- Carriers
- 4
This route sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 2,443 DEN to MIA flights, of which American Airlines flew 890 at 77.8% on time.
Best time to fly DEN to MIA: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 81.6% of the time and Tuesday flights 81.0%, against 74.9% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
74.9%
Arrivals under 15 minutes late, of 2,420 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
0.49%
National rate is 1.89%
Best carrier
American
77.8% on time across 890 flights
These figures cover 2,443 flights between September 2025 and August 2026. Beyond the headline rate, 8.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on DEN to MIA
The two carriers here are closely matched: 2 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines | 890 | 77.8% | 96 min | 1.01% | B |
| United Airlines | 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+ |
No carrier stands out. American tops the table at 77.8%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on DEN to MIA
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Denver to Miami
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 2 of the top 4 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. DEN → FLLDenver to Fort Lauderdale | United Airlines | 80.8% | 81.0% | 0.26% | 11am–2pm, Tue | UA 2188 09:47 |
| 2. DEN → MIADenver to Miami | American Airlines | 77.0% | 77.8% | 1.01% | 5am–8am, Tue | — |
| 3. DEN → MIADenver to Miami | United Airlines | 76.3% | 76.3% | 0.00% | 2pm–5pm, Tue | — |
| 4. DEN → FLLDenver to Fort Lauderdale | Southwest Airlines | 63.6% | 63.9% | 0.52% | 8am–11am, Mon | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 11 points, against 2 points between the best and worst carrier.
- 5am–8am127 flights81.6%
- 8am–11am518 flights75.3%
- 11am–2pm537 flights71.6%
- 2pm–5pm413 flights75.9%
- 5pm–8pm142 flights71.1%
- 8pm–5am706 flights76.1%
Scale runs 65% to 85%.
Book the early departure. Flights leaving between 5am–8am arrive on time 81.6% of the time, against 71.1% for the evening window. That is 11 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 706 flights scheduled in it.
Explore
Filter DEN to MIA by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On DEN to MIA, the best departure window is 5am–8am at 81.6% on time and the worst is 5pm–8pm at 71.1%, a wide gap of 10.5 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am81.6%
- 8–11am75.3%
- 11am–2pm71.6%
- 2–5pm75.9%
- 5–8pm71.1%
- 8pm–5am76.1%
best all US flightsScale 60% to 95%.
Across the year
When delays peak on this route
This route's year swings by 25 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
July is the worst month at 63.3% on time, 25 points below February, the best at 88.3%. 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 279 flights.
Across the week, Tuesday is the strongest day at 81.0% on time and Friday the weakest at 66.4%, a spread of 15 points.
Delay causes
Why this route gets delayed
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 42,000 reported delay minutes.
- 38%Carrier
- 37%Late-arriving aircraft
- 23%National Airspace System
- 1%Extreme weather
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 42,000 reported delay minutes here, that single category outweighs weather by 27 to one. The split is drawn from 42,301 reported delay minutes.
The largest share of delay minutes, 38%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 16,000 of the 42,000 delay minutes reported here.
Cancellations are rare at 0.49%, 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 actually costs
8.3% 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 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 runs 76.8% on time across 2,444 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 2,443 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.
Work out the risk of missing a connection in MIA after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 88.3% on time and July 63.3%, a swing of 25 points. If the dates move at all, move them out of July before you think about anything else. 2,420 completed flights over 12 months sit behind that.
Common questions
DEN to MIA questions
How often is DEN to MIA delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.1% of the 2,443 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on DEN to MIA?
American Airlines leads at 77.8% on time across 890 flights. United Airlines is at the other end on 76.3%, a gap of 2 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 DEN to MIA?
The 5am–8am departure window is the strongest at 81.6% on time. The 5pm–8pm window is the weakest at 71.1%, 11 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 DEN to MIA?
July is the weakest month at 63.3% on time, compared with 88.3% in February. 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.
Related
Where to go next
- MIA to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- Miami International (MIA) delay statistics
- American Airlines on DEN to MIA77.8%
- United Airlines on DEN to MIA76.3%
- Frontier Airlines on DEN to MIA73.9%
- Southwest Airlines on DEN to MIA64.5%
- DEN to PHX, a related route75.6%
- ATL to MIA, a related route71.2%
- DEN to SLC, a related route78.2%
- American Airlines on-time record77.8%
- United Airlines on-time record76.3%
- Frontier Airlines on-time record73.9%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. DEN to MIA and MIA to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.