Route reliability record
MIA→ATL
Miami to Atlanta
- Flights
- 6,271
- Period
- September 2025 to August 2026
- Distance
- 594 mi
- Carriers
- 6
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, 3 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 6,271 MIA to ATL flights, of which Delta Air Lines flew 3,322 at 77.8% on time.
Best time to fly MIA to ATL: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 91.4% of the time and Wednesday flights 81.9%, against 74.2% for the route overall.
Delta Air Lines is the most reliable of the three carriers covered here at 77.8% on time across 3,322 flights.
Key figures
On time
74.2%
Arrivals under 15 minutes late, of 6,163 completed flights
Avg delay
82 min
Across delayed arrivals only, not all flights
Cancelled
1.59%
National rate is 1.89%
Best carrier
Delta
77.8% on time across 3,322 flights
These figures cover 6,271 flights between September 2025 and August 2026. Beyond the headline rate, 10.3% 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 MIA to ATL
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 77.8% of the time; American Airlines manages 68.0%. Sample sizes sit next to every figure, because a two-point gap across 1,552 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Airthin sample | 184 | 83.9% | 49 min | 1.63% | B |
| Delta Air Lines | 3,322 | 77.8% | 82 min | 1.78% | B |
| Spirit Airlinesthin sample | 236 | 75.1% | 64 min | 4.66% | B− |
| Frontier Airlines | 933 | 69.7% | 84 min | 1.82% | C |
| American Airlines | 1,552 | 68.0% | 85 min | 0.64% | C+ |
| Republic Airwaysthin sample | 44 | 65.9% | 60 min | 0.00% | C+ |
Delta leads American by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on MIA to ATL
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 151012:0083.5% · 365 flights
- Delta 133214:0973.7% · 365 flights
- Delta 126106:0093.1% · 365 flights
- Delta 121107:1092.5% · 357 flights
- Delta 283610:4087.0% · 354 flights
- Delta 138618:1558.1% · 340 flights
- Frontier 440519:0954.8% · 336 flights
- Delta 157916:0067.1% · 325 flights
- Frontier 248305:0581.4% · 315 flights
- Delta 124906:0092.7% · 296 flights
- Delta 132316:4459.9% · 290 flights
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Best ways to make this trip
The most reliable ways to fly Miami to Atlanta
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 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. FLL → ATLFort Lauderdale to Atlanta | Delta Air Lines | 77.0% | 78.5% | 1.92% | 5am–8am, Wed | DL 1168 05:25 |
| 2. MIA → ATLMiami to Atlanta | Delta Air Lines | 76.4% | 77.8% | 1.78% | 5am–8am, Wed | DL 1261 06:00 |
| 3. MIA → ATLMiami to Atlanta | Frontier Airlines | 68.4% | 69.7% | 1.82% | 5am–8am, Wed | F9 2483 05:05 |
| 4. MIA → ATLMiami to Atlanta | American Airlines | 67.6% | 68.0% | 0.64% | 5am–8am, Tue | — |
| 5. FLL → ATLFort Lauderdale to Atlanta | Frontier Airlines | 61.7% | 63.7% | 3.18% | 5am–8am, Wed | F9 2173 06:00 |
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 33 points, against 10 points between the best and worst carrier.
- 5am–8am1,152 flights91.4%
- 8am–11am1,159 flights86.6%
- 11am–2pm792 flights79.7%
- 2pm–5pm1,167 flights66.5%
- 5pm–8pm1,347 flights58.1%
- 8pm–5am654 flights61.9%
Scale runs 50% to 95%.
The 5pm–8pm window is where this operation falls apart: 58.1% on time, against 91.4% 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 1,347 flights scheduled in it.
Explore
Filter MIA to ATL 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 MIA to ATL, the best departure window is 5am–8am at 91.4% on time and the worst is 5pm–8pm at 58.1%, a wide gap of 33.3 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am91.4%
- 8–11am86.6%
- 11am–2pm79.7%
- 2–5pm66.5%
- 5–8pm58.1%
- 8pm–5am61.9%
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 61.2% on time, 17 points below October, the best at 78.6%. 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 584 flights.
Across the week, Wednesday is the strongest day at 81.9% on time and Sunday the weakest at 63.1%, a spread of 19 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.
- 40%Late-arriving aircraft
- 34%Carrier
- 22%National Airspace System
- 4%Extreme weather
- 0%Security
40% 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 9 to one. The split is drawn from 130,044 reported delay minutes.
The largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 45,000 of the 130,000 delay minutes reported here.
Cancellations sit at 1.59% against a national 1.89%, which is ordinary. Diversions add another 0.13%.
Connections and stage length
What a delay here actually costs
10.3% 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 71.2% on time across 6,280 flights, 3 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 3 points of difference.
The sample behind these figures is 6,271 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 ATL 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. October runs 78.6% on time and July 61.2%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else. 6,163 completed flights over 12 months sit behind that.
Common questions
MIA to ATL questions
How often is MIA to ATL 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 25.8% of the 6,271 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 MIA to ATL?
Delta Air Lines leads at 77.8% on time across 3,322 flights. American Airlines is at the other end on 68.0%, a gap of 10 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 MIA to ATL?
The 5am–8am departure window is the strongest at 91.4% on time. The 5pm–8pm window is the weakest at 58.1%, 33 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 MIA to ATL?
July is the weakest month at 61.2% on time, compared with 78.6% in October. 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
- ATL to MIA — the return legseparate record
- Miami International (MIA) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Envoy Air on MIA to ATL83.9%
- Delta Air Lines on MIA to ATL77.8%
- Spirit Airlines on MIA to ATL75.1%
- Frontier Airlines on MIA to ATL69.7%
- American Airlines on MIA to ATL68.0%
- MIA to LGA, a related route67.4%
- LGA to ATL, a related route75.5%
- MIA to DFW, a related route75.1%
- Envoy Air on-time record83.9%
- Delta Air Lines on-time record77.8%
- Spirit Airlines on-time record75.1%
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
Direction matters. MIA to ATL and ATL to MIA 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.