Route reliability record
SJU→JFK
San Juan to New York
- Flights
- 3,560
- Period
- September 2025 to August 2026
- Distance
- 1,598 mi
- Carriers
- 3
This route carries a cancellation problem, not just a delay problem: 3.9% of scheduled flights never operate, against 1.9% 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 3,560 SJU to JFK flights, of which Delta Air Lines flew 1,104 at 87.7% on time.
Best time to fly SJU to JFK: a 5am–8am departure, ideally on a Friday. Flights in that window arrived on time 87.2% of the time and Friday flights 82.1%, against 77.8% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.8%
Arrivals under 15 minutes late, of 3,412 completed flights
Avg delay
82 min
Across delayed arrivals only, not all flights
Cancelled
3.93%
National rate is 1.89%
Best carrier
Delta
87.7% on time across 1,104 flights
These figures cover 3,560 flights between September 2025 and August 2026. Beyond the headline rate, 8.8% 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 SJU to JFK
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 87.7% of the time; JetBlue Airways manages 72.4%. Sample sizes sit next to every figure, because a two-point gap across 2,250 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,104 | 87.7% | 76 min | 2.36% | A |
| Frontier Airlinesthin sample | 206 | 81.4% | 68 min | 2.43% | B |
| JetBlue Airways | 2,250 | 72.4% | 85 min | 4.84% | C− |
JetBlue Airways cancels 4.8% 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.
Flight by flight
Flights on SJU to JFK
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.
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Best ways to make this trip
The most reliable ways to fly San Juan to New York
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 4 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SJU → JFKSan Juan to New York | Delta Air Lines | 85.6% | 87.7% | 2.36% | 5am–8am, Fri | DL 1854 07:00 |
| 2. SJU → EWRSan Juan to Newark | United Airlines | 75.2% | 77.4% | 2.79% | 5pm–8pm, Wed | UA 2036 18:45 |
| 3. SJU → EWRSan Juan to Newark | JetBlue Airways | 69.1% | 71.3% | 3.07% | 8am–11am, Sat | — |
| 4. SJU → JFKSan Juan to New York | JetBlue Airways | 68.9% | 72.4% | 4.84% | 8am–11am, Thu | B6 1604 14:25 |
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 23 points, against 15 points between the best and worst carrier.
- 5am–8am872 flights87.2%
- 8am–11am373 flights84.2%
- 11am–2pm627 flights74.2%
- 2pm–5pm453 flights74.1%
- 5pm–8pm774 flights76.9%
- 8pm–5am461 flights63.8%
Scale runs 55% to 95%.
The 8pm–5am window is where this operation falls apart: 63.8% on time, against 87.2% 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 5am–8am window is the busiest, with 872 flights scheduled in it.
Explore
Filter SJU to JFK 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 SJU to JFK, the best departure window is 5am–8am at 87.2% on time and the worst is 8pm–5am at 63.8%, a wide gap of 23.4 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am87.2%
- 8–11am84.2%
- 11am–2pm74.2%
- 2–5pm74.1%
- 5–8pm76.9%
- 8pm–5am63.8%
best all US flightsScale 55% to 95%.
Across the year
When delays peak on this route
This route's year swings by 31 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 57.7% on time, 31 points below May, the best at 88.5%. 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 351 flights.
Across the week, Friday is the strongest day at 82.1% on time and Sunday the weakest at 73.8%, a spread of 8 points.
Delay causes
Why this route gets delayed
Carrier accounts for 44% of the 62,000 delay minutes carriers reported here, and the remaining four split what is left.
- 44%Carrier
- 43%Late-arriving aircraft
- 11%National Airspace System
- 1%Extreme weather
- 0%Security
43% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 62,000 reported delay minutes here, that single category outweighs weather by 29 to one. The split is drawn from 62,366 reported delay minutes.
The largest share of delay minutes, 44%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 28,000 of the 62,000 delay minutes reported here.
Cancellations run at 3.93%, against 1.89% nationally. That is about one flight in 25 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
8.8% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last an hour and a half, which a normal layover absorbs.
At 1,598 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 70.2% on time across 3,554 flights, 8 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 8 points of difference.
The sample behind these figures is 3,560 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 JFK after this flight
What to do with this
Booking this route
Put together: the delay figures matter less here than the 3.93% cancellation rate. A late arrival costs you an hour and a half; 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. 3,412 completed flights over 12 months sit behind that.
Common questions
SJU to JFK questions
How often is SJU to JFK delayed?
Roughly one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.2% of the 3,560 flights in this analysis, against 22.7% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on SJU to JFK?
Delta Air Lines leads at 87.7% on time across 1,104 flights. JetBlue Airways is at the other end on 72.4%, a gap of 15 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 SJU to JFK?
The 5am–8am departure window is the strongest at 87.2% on time. The 8pm–5am window is the weakest at 63.8%, 23 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 SJU to JFK?
July is the weakest month at 57.7% on time, compared with 88.5% in May. Across the year that is 31 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
- JFK to SJU — the return legseparate record
- Luis Munoz Marin International (SJU) delay statistics
- John F. Kennedy International (JFK) delay statistics
- Delta Air Lines on SJU to JFK87.7%
- Frontier Airlines on SJU to JFK81.4%
- JetBlue Airways on SJU to JFK72.4%
- SJU to MCO, a related route78.0%
- LAX to JFK, a related route77.5%
- SJU to MIA, a related route78.9%
- Delta Air Lines on-time record87.7%
- Frontier Airlines on-time record81.4%
- JetBlue Airways on-time record72.4%
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Direction matters. SJU to JFK and JFK to SJU 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.