Route reliability record
ATL→MIA
Atlanta to Miami
- Flights
- 6,280
- Period
- September 2025 to August 2026
- Distance
- 594 mi
- Carriers
- 6
This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 6,280 ATL to MIA flights, of which American Airlines flew 1,555 at 74.8% on time.
Best time to fly ATL to MIA: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 88.5% of the time and Wednesday flights 80.5%, against 71.2% for the route overall.
American Airlines is the most reliable of the three carriers covered here at 74.8% on time across 1,555 flights.
Key figures
On time
71.2%
Arrivals under 15 minutes late, of 6,162 completed flights
Avg delay
73 min
Across delayed arrivals only, not all flights
Cancelled
1.61%
National rate is 1.89%
Best carrier
American
74.8% on time across 1,555 flights
These figures cover 6,280 flights between September 2025 and August 2026. Beyond the headline rate, 11.0% 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 ATL to MIA
The choice of carrier is not cosmetic here. American Airlines arrives on time 74.8% of the time; Frontier Airlines manages 63.4%. Sample sizes sit next to every figure, because a two-point gap across 937 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Airthin sample | 187 | 75.0% | 79 min | 1.60% | B |
| American Airlines | 1,555 | 74.8% | 92 min | 0.77% | C+ |
| Spirit Airlinesthin sample | 236 | 74.7% | 96 min | 4.66% | C− |
| Delta Air Lines | 3,321 | 71.4% | 56 min | 1.81% | C |
| Republic Airwaysthin sample | 44 | 63.6% | 68 min | 0.00% | D+ |
| Frontier Airlines | 937 | 63.4% | 96 min | 1.60% | D |
American leads Frontier by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on ATL 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.
- Delta 151008:5583.7% · 365 flights
- Delta 133211:0082.2% · 365 flights
- Delta 158818:5564.2% · 364 flights
- Delta 132313:4562.4% · 363 flights
- Delta 157912:1575.3% · 361 flights
- Frontier 440611:4772.5% · 349 flights
- Delta 283607:3089.8% · 345 flights
- Delta 138615:1563.2% · 337 flights
- Frontier 344222:5048.6% · 305 flights
- Delta 123422:3061.4% · 274 flights
- Delta 158922:5769.9% · 255 flights
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Best ways to make this trip
The most reliable ways to fly Atlanta 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. 3 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. ATL → MIAAtlanta to Miami | American Airlines | 74.2% | 74.8% | 0.77% | 5am–8am, Wed | — |
| 2. ATL → FLLAtlanta to Fort Lauderdale | Delta Air Lines | 72.6% | 73.9% | 1.78% | 5am–8am, Wed | DL 1334 07:25 |
| 3. ATL → MIAAtlanta to Miami | Delta Air Lines | 70.1% | 71.4% | 1.81% | 5am–8am, Wed | DL 2836 07:30 |
| 4. ATL → FLLAtlanta to Fort Lauderdale | JetBlue Airways | 67.3% | 69.7% | 3.38% | 5am–8am, Wed | B6 1797 07:00 |
| 5. ATL → FLLAtlanta to Fort Lauderdale | Frontier Airlines | 62.4% | 64.0% | 2.48% | 5am–8am, Tue | F9 2174 22:48 |
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 30 points, against 11 points between the best and worst carrier.
- 5am–8am866 flights88.5%
- 8am–11am1,344 flights79.0%
- 11am–2pm1,142 flights76.5%
- 2pm–5pm1,101 flights62.2%
- 5pm–8pm746 flights58.2%
- 8pm–5am1,081 flights60.2%
Scale runs 50% to 95%.
The 5pm–8pm window is where this operation falls apart: 58.2% on time, against 88.5% 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 8am–11am window is the busiest, with 1,344 flights scheduled in it.
Explore
Filter ATL 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 ATL to MIA, the best departure window is 5am–8am at 88.5% on time and the worst is 5pm–8pm at 58.2%, a wide gap of 30.3 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am88.5%
- 8–11am79.0%
- 11am–2pm76.5%
- 2–5pm62.2%
- 5–8pm58.2%
- 8pm–5am60.2%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 17 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 63.4% on time, 17 points below September, the best at 80.1%. 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. December was the busiest month here, with 587 flights.
Across the week, Wednesday is the strongest day at 80.5% on time and Sunday the weakest at 62.6%, a spread of 18 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 130,000 reported delay minutes.
- 38%Late-arriving aircraft
- 37%Carrier
- 20%National Airspace System
- 5%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 130,000 reported delay minutes here, that single category outweighs weather by 8 to one. The split is drawn from 129,764 reported delay minutes.
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 48,000 of the 130,000 delay minutes reported here.
Cancellations sit at 1.61% against a national 1.89%, which is ordinary. Diversions add another 0.27%.
Connections and stage length
What a delay here actually costs
11.0% 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 594 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 74.2% on time across 6,271 flights, 3 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 3 points of difference.
The sample behind these figures is 6,280 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. September runs 80.1% on time and July 63.4%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else. 6,162 completed flights over 12 months sit behind that.
Common questions
ATL to MIA questions
How often is ATL to MIA delayed?
Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 28.8% of the 6,280 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 ATL to MIA?
American Airlines leads at 74.8% on time across 1,555 flights. Frontier Airlines is at the other end on 63.4%, a gap of 11 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 ATL to MIA?
The 5am–8am departure window is the strongest at 88.5% on time. The 5pm–8pm window is the weakest at 58.2%, 30 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 ATL to MIA?
July is the weakest month at 63.4% on time, compared with 80.1% in September. Across the year that is 17 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 ATL — the return legseparate record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Miami International (MIA) delay statistics
- Envoy Air on ATL to MIA75.0%
- American Airlines on ATL to MIA74.8%
- Spirit Airlines on ATL to MIA74.7%
- Delta Air Lines on ATL to MIA71.4%
- Frontier Airlines on ATL to MIA63.4%
- ATL to LGA, a related route72.3%
- LGA to MIA, a related route69.9%
- ATL to MCO, a related route70.3%
- Envoy Air on-time record75.0%
- American Airlines on-time record74.8%
- Spirit Airlines on-time record74.7%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. ATL to MIA and MIA to ATL 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.