Route reliability record

MIA→JFK

Miami to New York

Flights: 4,608
Period: June 2025 to May 2026
Distance: 1,089 mi
Carriers: 4

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 77.4%. The late ones land a little over an hour behind schedule. That rests on 4,608 flights, of which Delta Air Lines flew 1,620 at 70.7% on time.

The national on-time rate over the same period is 77.4%, so this route runs 6 points behind the country as a whole. Across a thousand flights that is about 63 extra late arrivals.

On time

71.1%

Arrivals under 15 minutes late, of 4,459 completed flights

Avg delay

80 min

Across delayed arrivals only, not all flights

Cancelled

2.99%

National rate is 1.80%

Best carrier

Delta

70.7% on time across 1,620 flights

These figures cover 4,608 flights between June 2025 and May 2026. Beyond the headline rate, 11.6% 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 airline is most reliable on MIA to JFK

The two carriers here are closely matched: half a point 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.

On-time performance by carrier on MIA to JFK
Airline	Flights	On time	Avg delay	Cancelled	Grade
Frontier Airlinesthin sample	305	78.6%	95 min	1.97%	B
JetBlue Airwaysthin sample	28	71.4%	58 min	0.00%	C+
Delta Air Lines	1,620	70.7%	82 min	3.27%	C−
American Airlines	2,655	70.5%	78 min	2.98%	C

Delta Air Lines cancels 3.3% 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.

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 35 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am846 flights91.6%
8am–11am631 flights83.7%
11am–2pm631 flights73.0%
2pm–5pm895 flights65.2%
5pm–8pm847 flights56.5%
8pm–5am758 flights59.3%

Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 56.5% on time, against 91.6% 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.

Across the year

When delays peak on this route

This route's year swings by 23 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, June worst

June is the worst month at 62.7% on time, 23 points below September, the best at 85.4%. 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.

Across the week, Wednesday is the strongest day at 76.0% on time and Sunday the weakest at 60.2%. 16 points is a smaller lever than departure hour, but it is free.

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 103,000 reported delay minutes.

Late-arriving aircraft
37%
Carrier
31%
National Airspace System
25%
Extreme weather
7%
Security
0%

37% 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 103,000 reported delay minutes here, that single category outweighs weather by 6 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 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 91.6% on time here.

Cancellations run at 2.99%, against 1.80% nationally. That is roughly one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and stage length

What a delay here actually costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.6% of arrivals land a full hour or more behind schedule, against 8.2% 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.

The 1,089 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg is a different operation and performs like one: it runs 75.7% on time across 4,607 flights, 5 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 5 points of difference.

The sample behind these figures is 4,608 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.

What to do with this

Booking this route

Put together: the delay figures matter less here than the 2.99% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic.

Common questions

MIA to JFK questions

How often is MIA to JFK delayed?

Roughly one flight in three arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 28.9% of the 4,608 flights in this analysis, against 22.6% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on MIA to JFK?

Delta Air Lines leads at 70.7% on time across 1,620 flights. American Airlines is at the other end on 70.5%, a gap of half a point. 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 JFK?

The 5am–8am departure window is the strongest at 91.6% on time. The 5pm–8pm window is the weakest at 56.5%, 35 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 June delays on MIA to JFK?

June is the weakest month at 62.7% on time, compared with 85.4% in September. Across the year that is 23 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

Direction matters. MIA to JFK and JFK to MIA are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

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

Key figures