Carrier route record
DLJFK→MIA
Delta Air Lines · New York to Miami
- Flights
- 1,620
- Period
- July 2025 to June 2026
- Share of route
- 36%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on JFK to MIA carries a cancellation problem, not just a delay problem: 3.2% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, close to three flights in four arrive on time, worth a B− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 1,620 flights, with a median arrival 9 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Delta on JFK to MIA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.1%
Arrivals under 15 minutes late, of 1,563 completed flights
Avg delay
74 min
Across delayed arrivals only, not all flights
Cancelled
3.21%
National rate is 1.81%
Whole route
77.3%
Every carrier on JFK to MIA, 4,553 flights
These figures cover 1,620 flights between July 2025 and June 2026. Beyond the headline rate, 8.9% 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
Delta against every carrier on JFK to MIA
Delta flew 1,620 of the 4,553 flights on JFK to MIA, about 36% of it. Its 76.1% on time is about level with the route as a whole at 77.3%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from Frontier at 79.4% to Delta at 76.1%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 274 | 79.4% | 112 min | 2.55% | B |
| American Airlines | 2,659 | 77.8% | 103 min | 2.71% | B |
| Delta Air Lines (this page) | 1,620 | 76.1% | 74 min | 3.21% | B− |
Flight by flight
Delta flight numbers on JFK to MIA
Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 17 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–8am363 flights84.4%
- 8am–11am—
- 11am–2pm542 flights78.9%
- 2pm–5pm256 flights71.0%
- 5pm–8pm153 flights72.7%
- 8pm–5am306 flights67.0%
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 84.4% of the time, against 67.0% for the overnight window. That is 17 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 542 flights scheduled in it.
Across the year
Delta on JFK to MIA through the year
December is the weak month at 63.4% on time, against 87.9% in April. 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 155 flights.
Across the week, Wednesday is the strongest day at 82.3% on time and Sunday the weakest at 64.2%. 18 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Delta runs late on this route
One category carries most of the weight here. Carrier accounts for 43% of the 28,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 43%Carrier
- 33%National Airspace System
- 22%Late-arriving aircraft
- 2%Extreme weather
- 0%Security
The largest share of delay minutes, 43%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 12,000 of the 28,000 delay minutes reported here. The split is drawn from 27,668 reported delay minutes.
33% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 8,995 minutes out of 28,000, against a national NAS share of 21%.
Cancellations run at 3.21%, against 1.81% nationally. That is about 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 costs
8.9% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
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 72.0% on time across 1,620 flights, 4 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 4 points of difference.
The sample behind these figures is 1,620 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 Delta on JFK to MIA
Put together: the delay figures matter less here than the 3.21% 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. 1,563 completed flights over 12 months sit behind that.
Related
Where to go next
- JFK to MIA, every carrier
- Delta on MIA to JFK, the return leg
- Frontier Airlines on JFK to MIA79.4%
- American Airlines on JFK to MIA77.8%
- Delta Air Lines network-wide record
- John F. Kennedy International (JFK) delay statistics
- Miami International (MIA) delay statistics
- The US routes with the most cancellations
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.