Miami, FL · departure reliability

MIA

Miami International

Departures: 111,061
Period: July 2025 to June 2026
Carriers: 9
US rank: #20 by volume

Terminal building and aircraft stands at a US airport

Miami

Miami International sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 111,061 flights, of which Envoy Air flew 13,859 at 83.1% on time.

Envoy Air is the most reliable of the nine carriers covered here at 83.1% on time across 13,859 flights.

On time

73.8%

Departures arriving under 15 minutes late at their destination

Avg delay

72 min

Across delayed flights only

Cancelled

1.62%

National rate is 1.81%

Best carrier

Envoy

83.1% on time here

These figures cover 111,000 flights between July 2025 and June 2026. Beyond the headline rate, 9.7% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

Which airlines run best out of MIA

The choice of carrier is not cosmetic here. Envoy Air arrives on time 83.1% of the time; Spirit Airlines manages 65.8%. Sample sizes sit next to every figure, because a two-point gap across 3,516 flights means less than a ten-point one.

On-time performance by carrier departing MIA
Airline	Flights	On time	Avg delay	Cancelled	Grade
American Airlines	63,941	71.9%	73 min	1.61%	C
Envoy Air	13,859	83.1%	48 min	0.84%	B+
Delta Air Lines	11,625	74.1%	78 min	2.10%	C
United Airlines	6,839	77.9%	83 min	1.01%	B
Southwest Airlines	5,316	71.6%	59 min	1.13%	C
Frontier Airlines	4,274	75.1%	86 min	2.20%	B
Spirit Airlines	3,516	65.8%	78 min	4.64%	C−
Republic Airways	1,069	68.6%	86 min	1.31%	C
Alaska Airlines	533	69.6%	56 min	1.50%	C

Spirit Airlines cancels 4.6% 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

Busiest routes out of MIA

Route-level records vary far more than the airport average. These are the 25 busiest departures from MIA, each with its own on-time rate against the airport-wide 73.8%.

Busiest routes from MIA by flight volume
Route	Flights	On time	Avg delay	Cancelled	Grade
MIA to ATL · Atlanta	6,223	73.7%	80 min	1.41%	C
MIA to LGA · New York	6,010	68.0%	77 min	4.09%	C−
MIA to DFW · Dallas-Fort Worth	4,825	73.1%	78 min	2.80%	C
MIA to JFK · New York	4,555	71.9%	82 min	2.83%	C
MIA to ORD · Chicago	4,447	70.8%	75 min	1.96%	C
MIA to EWR · Newark	3,985	71.8%	82 min	2.69%	C
MIA to DCA · Washington	3,962	74.7%	70 min	2.15%	C
MIA to MCO · Orlando	3,804	72.1%	72 min	1.00%	C
MIA to IAH · Houston	3,737	77.2%	80 min	1.12%	B
MIA to CLT · Charlotte	3,726	78.1%	74 min	1.69%	B
MIA to BOS · Boston	3,415	69.7%	73 min	2.40%	C
MIA to LAX · Los Angeles	3,245	75.2%	69 min	0.59%	B+
MIA to PHL · Philadelphia	3,158	75.8%	79 min	2.28%	B
MIA to TPA · Tampa	2,947	70.6%	79 min	1.15%	C
MIA to SJU · San Juan	2,636	74.7%	76 min	0.95%	C+
MIA to BNA · Nashville	2,503	71.4%	69 min	1.24%	C
MIA to DEN · Denver	2,491	77.1%	68 min	0.52%	B+
MIA to RDU · Raleigh	2,347	71.4%	76 min	1.70%	C
MIA to BWI · Baltimore	2,284	73.6%	62 min	1.97%	C
MIA to AUS · Austin	2,161	72.8%	73 min	1.06%	C
MIA to PHX · Phoenix	1,834	77.9%	65 min	0.76%	B+
MIA to DTW · Detroit	1,813	72.9%	78 min	1.43%	C
MIA to SFO · San Francisco	1,725	71.6%	65 min	0.70%	C+
MIA to MSY · New Orleans	1,532	72.8%	62 min	1.17%	C
MIA to JAX · Jacksonville	1,526	74.1%	62 min	0.85%	C+

Departure window

The best time of day to leave MIA

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 25 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am13,330 flights89.8%
8am–11am16,894 flights86.3%
11am–2pm12,609 flights74.7%
2pm–5pm19,549 flights68.4%
5pm–8pm21,810 flights64.7%
8pm–5am26,869 flights68.6%

Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 64.7% on time, against 89.8% 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 8pm–5am window is the busiest, with 26,869 flights scheduled in it.

Across the year

When MIA runs late

MIA's year swings by 15 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.

Darker means more delays. Figures are on-time percentages.September best, July worst

July is the worst month at 63.6% on time, 15 points below September, 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. March was the busiest month here, with 10,460 flights.

Across the week, Tuesday is the strongest day at 79.3% on time and Sunday the weakest at 64.8%. 15 points is a smaller lever than departure hour, but it is free.

Delay causes

Why MIA 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 2.05 million reported delay minutes.

Late-arriving aircraft
40%
Carrier
32%
National Airspace System
22%
Extreme weather
5%
Security
0%

40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 2.05 million reported delay minutes here, that single category outweighs weather by 8 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 2,047,381 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 89.8% on time here.

Cancellations sit at 1.62% against a national 1.81%, which is ordinary. Diversions add another 0.36%.

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.7% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

111,061 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.

What to do with this

Flying out of MIA

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 78.6% on time and July 63.6%, a swing of 15 points. If the dates move at all, move them out of July before you think about anything else. 108,862 completed flights over 12 months sit behind that.

Common questions

MIA delay questions

How often is Miami (MIA) delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 26.2% of the 111,061 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on Miami (MIA)?

Envoy Air leads at 83.1% on time across 13,859 flights. Spirit Airlines is at the other end on 65.8%, a gap of 17 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 Miami (MIA)?

The 5am–8am departure window is the strongest at 89.8% on time. The 5pm–8pm window is the weakest at 64.7%, 25 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 Miami (MIA)?

July is the weakest month at 63.6% on time, compared with 78.6% in September. Across the year that is 15 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures