Carrier performance at one airport
DL→MIA
Delta Air Lines at Miami International
- Departures
- 11,676
- Period
- September 2025 to August 2026
- Routes
- 12
- Rank here
- #3 of 9
Delta Air Lines at Miami sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 11,676 flights, of which Envoy Air flew 14,383 at 83.0% on time.
Measured against the airport rather than the country, Delta Air Lines runs half a point ahead of the 74.2% weighted average across all carriers at MIA. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
74.7%
11,386 completed departures
Avg delay
78 min
Across delayed flights only
Cancelled
2.21%
At MIA, this carrier only
Rank here
#3
Of 9 carriers clearing the floor at MIA
These figures cover 12,000 flights between September 2025 and August 2026. Beyond the headline rate, 9.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Against the competition
Every carrier at MIA, ranked
The choice of carrier is not cosmetic here. Envoy Air arrives on time 83.0% of the time; Spirit Airlines manages 65.3%. Sample sizes sit next to every figure, because a two-point gap across 2,803 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Air | 14,383 | 83.0% | 50 min | 0.82% | B+ |
| United Airlines | 6,757 | 78.7% | 84 min | 1.11% | B |
| Delta Air Lines (this page) | 11,676 | 74.7% | 78 min | 2.21% | C |
| Frontier Airlines | 4,358 | 73.7% | 85 min | 2.36% | C |
| American Airlines | 64,336 | 72.5% | 73 min | 1.61% | C |
| Alaska Airlines | 533 | 72.4% | 55 min | 1.31% | C |
| Southwest Airlines | 5,373 | 69.7% | 57 min | 1.17% | C |
| Republic Airways | 909 | 69.4% | 91 min | 1.54% | C |
| Spirit Airlines | 2,803 | 65.3% | 75 min | 5.35% | C− |
Spirit Airlines cancels 5.3% 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 Delta Air Lines flies from MIA
Delta Air Lines operates 12 routes out of MIA 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.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| MIA to ATL · Atlanta | 3,322 | 77.8% | 82 min | 1.78% | B |
| MIA to LGA · New York | 1,916 | 73.4% | 64 min | 3.91% | C− |
| MIA to JFK · New York | 1,621 | 72.2% | 75 min | 3.45% | C− |
| MIA to DTW · Detroit | 930 | 76.9% | 92 min | 1.08% | B |
| MIA to BOS · Boston | 890 | 69.6% | 78 min | 2.70% | C |
| MIA to MSP · Minneapolis | 759 | 77.6% | 75 min | 0.79% | B+ |
| MIA to LAX · Los Angeles | 494 | 77.7% | 80 min | 1.62% | B |
| MIA to SEA · Seattle | 366 | 63.4% | 90 min | 1.64% | D |
| MIA to SLC · Salt Lake Citythin sample | 364 | 80.1% | 65 min | 0.55% | B+ |
| MIA to DCA · Washingtonthin sample | 363 | 78.9% | 73 min | 0.55% | B+ |
| MIA to RDU · Raleighthin sample | 360 | 67.3% | 88 min | 1.94% | C |
| MIA to AUS · Austinthin sample | 284 | 69.4% | 86 min | 1.06% | C |
Flight by flight
Delta Air Lines flight numbers from MIA
13 Delta Air Lines flight numbers leaving MIA flew their main route often enough to have a record of their own. Grouped by destination.
- DL 1211to ATL 07:1092.5%
- DL 1249to ATL 06:0092.7%
- DL 1261to ATL 06:0093.1%
- DL 1386to ATL 18:1558.1%
- DL 2836to ATL 10:4087.0%
- DL 2344to AUS 19:1569.4%
- DL 2888to DCA 11:2273.3%
- DL 2428to JFK 07:4088.7%
- DL 450to LAX 07:5081.9%
- DL 2339to LGA 08:1577.9%
- DL 2387to LGA 07:0086.5%
- DL 2992to RDU 18:2867.3%
- DL 2021to SLC 07:0080.7%
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 32 points, against 18 points between the best and worst carrier.
- 5am–8am2,159 flights89.7%
- 8am–11am1,373 flights88.1%
- 11am–2pm2,436 flights76.6%
- 2pm–5pm1,883 flights70.4%
- 5pm–8pm2,970 flights63.5%
- 8pm–5am855 flights58.0%
Scale runs 50% to 95%.
The 8pm–5am window is where this operation falls apart: 58.0% on time, against 89.7% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 2,970 flights scheduled in it.
Across the year
Seasonal pattern
December is the weak month at 67.3% on time, against 81.3% in June. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. March was the busiest month here, with 1,100 flights.
Delay causes
What holds this operation up
- 38%Late-arriving aircraft
- 35%Carrier
- 22%National Airspace System
- 4%Extreme weather
- 0%Security
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 223,000 reported delay minutes here, that single category outweighs weather by 9 to one. The split is drawn from 223,109 reported delay minutes.
Cancellations sit at 2.21% against a national 1.89%, which is ordinary. Diversions add another 0.27%.
9.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The sample behind these figures is 11,676 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.
Put together: the calendar is the biggest lever here, not the carrier or the hour. June runs 81.3% on time and December 67.3%, a swing of 14 points. If the dates move at all, move them out of December before you think about anything else. 11,386 completed flights over 12 months sit behind that.
Common questions
Delta Air Lines at MIA
How often is Delta Air Lines at 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 25.3% of the 11,676 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 Delta Air Lines at MIA?
Envoy Air leads at 83.0% on time across 14,383 flights. Spirit Airlines is at the other end on 65.3%, a gap of 18 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 Delta Air Lines at MIA?
The 5am–8am departure window is the strongest at 89.7% on time. The 8pm–5am window is the weakest at 58.0%, 32 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 December delays on Delta Air Lines at MIA?
December is the weakest month at 67.3% on time, compared with 81.3% in June. Across the year that is 14 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
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.