Route profile
JFK→SJU
Flight reliability, delays and best times to fly from New York to San Juan, 1,598 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 9% of comparable major US routes (4,598 compared)
Calculated from 11,338 flights. How this is calculated
JFK → SJU arrives on time 70.5% of the time; the return trip, SJU → JFK, arrives on time 79.0% of the time, an 8.5-point gap between the two directions of the same city pair.
JFK → SJU spends 32.7 minutes on the ground on a 1,598-mile trip: 26.5 minutes from pushback to wheels-up at JFK and 6.2 minutes from touchdown to gate at SJU.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
This route's worst arrivals run unusually far past its typical one, a bigger gap than 94% of 4,598 comparable routes.
A typical arrival is 4 min early, but the worst tenth run 75 minutes worse than that.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,598 in the comparison.
Why JFK → SJU flights are cancelled
July 2023 – July 2026
JFK → SJU cancelled 191 of 11,338 scheduled flights — about 1 in every 59. The reason filed most often was extreme weather, 37.2% of the cancellations coded on this route — about 1 in every 160 scheduled flights.
Share of cancellations
Of 191 cancelled departures carrying a reason code.
What each reason means
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
71 cancellations, 37.2% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
67 cancellations, 35.1% of the total.
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
48 cancellations, 25.1% of the total.
A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.
5 cancellations, 2.6% of the total.
Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.
191 coded cancellations were recorded on JFK → SJU; the section appears from 50.
When it goes wrong
July 2023 – July 2026
71 min late
against a median of 4 min early
JFK → SJU has an average that understates its risk: a typical arrival is 4 min early, but the worst tenth are 75 minutes worse than that. If the trip has something unmissable at the end of it, the median is the wrong number to plan against.
Percentiles over 11,338 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SJU after arriving from JFK.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 43% | Likely to miss |
| 45 min | 29% | High risk |
| 60 min | 20% | High risk |
| 90 min | 12% | Some risk |
| 120 min | 7.5% | Some risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 1.68% of the time and diverts 0.17% of the time, which a late arrival never shows up in.
Chance of missing is the share of 11,128 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 71 minutes late (90th-percentile gate arrival delay), over 11,338 operations.
Any other layover length: connection checker.
Best time to fly
JFK → SJU flights departing 5–9 AM arrived on time 80.6% of the time, against 59.5% for 6–9 PM departures, a gap of 21.1 percentage points.
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 81.3% on time from 613 flights
- 6 AM: 74.1% on time from 715 flights
- 7 AM: 83.1% on time from 380 flights
- 8 AM: 82.8% on time from 1,488 flights
- 9 AM: 66.0% on time from 348 flights
- 10 AM: 66.8% on time from 252 flights
- 11 AM: 68.2% on time from 824 flights
- 12 PM: 82.5% on time from 1,321 flights
- 1 PM: 62.2% on time from 621 flights
- 2 PM: 75.0% on time from 272 flights
- 3 PM: 69.3% on time from 405 flights
- 4 PM: 68.8% on time from 131 flights
- 5 PM: 67.3% on time from 416 flights
- 6 PM: 56.9% on time from 830 flights
- 7 PM: 65.2% on time from 821 flights
- 8 PM: 55.1% on time from 610 flights
- 9 PM: 61.1% on time from 659 flights
- 10 PM: 57.7% on time from 567 flights
- 11 PM: too few flights to score
Why JFK → SJU runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for JFK → SJU. Only delays of 15 minutes or more are attributed.
How this route holds up in bad weather
July 2023 – July 2026
The harder-hit end is the one the flight leaves from, where a cancellation keeps it from departing at all. Bad weather cancels 3.5 times the normal rate at JFK against barely any change at SJU. Cancelled in bad weather against normal hours: JFK 6.0% against 1.7%, SJU 1.5% against 1.4%. Flights that did leave JFK in bad weather arrived on time 64.1% of the time, against 79.7% in normal hours.
Bad weather and normal hours at the airports
Scheduled departures, July 2023 – July 2026| Departures from | JFK | SJU |
|---|---|---|
| Cancelled in bad weather | 6.0% | 1.5% |
| Cancelled in normal hours | 1.7% | 1.4% |
| Arrived on time, bad weather | 64.1% | 69.5% |
| Arrived on time, normal hours | 79.7% | 76.4% |
| Departures in bad weather | 46,497 | 2,333 |
Delta Air Lines (4.0% cancelled against 6.9% for the other carriers at JFK) and Frontier Airlines (4.6% cancelled against 6.5% for the other carriers at JFK) cancelled fewer departures from JFK in bad weather than the other carriers there did in the same months. None of the route’s other carriers was clearly worse.
This route’s airlines in bad weather at JFK
All departures from JFK| Airline | Bad-weather departures | Cancelled | Other carriers |
|---|---|---|---|
| Delta Air Lines | 12,657 | 4.0%below the others | 6.9% |
| Frontier Airlines | 672 | 4.6%below the others | 6.5% |
| JetBlue | 14,948 | 6.2%about level | 6.2% |
These are airport figures, not route figures: every scheduled departure from JFK and SJU, to any destination, in hours the weather report called bad. The airline rows count each carrier’s departures from JFK on every route.
Weather source and limits. In full: JFK (airlines), SJU, What Weather Costs Each Airport, Who Cancels More When the Weather Turns, Airports That Change Places When Weather Turns.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| JetBlue | 6,846 | 66.8% | 2.06% | -1 min | 14.7% |
| Delta Air Lines | 3,402 | 80.0% | 0.85% | -11 min | 6.4% |
| Frontier Airlines | 1,090 | 64.3% | 1.93% | 0 min | 12.0% |
JetBlue flew 60.4% of the 11,338 flights listed. JetBlue cancelled 2.06% of its flights here against 0.85% for Delta Air Lines.
Delta Air Lines arrived on time 15.7 percentage points more often than Frontier Airlines on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
DL1961 (12:25 PM) arrived on time 86.6% of the time, 26.9 points more often than B62903 (10:59 PM) at 59.7%.
Weekly and seasonal patterns
By day of week
Wednesday is historically the most reliable day and Sunday the least, a gap of 6.1 percentage points.
By month
- Jan: 68.4%
- Feb: 69.4%
- Mar: 68.9%
- Apr: 79.7%
- May: 79.4%
- Jun: 72.6%
- Jul: 59.2%
- Aug: 61.8%
- Sep: 74.1%
- Oct: 73.1%
- Nov: 79.6%
- Dec: 66.8%
July is historically the weakest month and April the strongest, a spread of 20.5 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 50.7% from 297 flights
- August 2023: 52.6% from 297 flights
- September 2023: 59.4% from 206 flights
- October 2023: 70.7% from 216 flights
- November 2023: 80.4% from 258 flights
- December 2023: 68.9% from 283 flights
- January 2024: 70.6% from 265 flights
- February 2024: 68.1% from 237 flights
- March 2024: 60.1% from 274 flights
- April 2024: 77.1% from 295 flights
- May 2024: 72.4% from 280 flights
- June 2024: 66.2% from 332 flights
- July 2024: 65.2% from 365 flights
- August 2024: 67.9% from 369 flights
- September 2024: 86.4% from 272 flights
- October 2024: 83.9% from 305 flights
- November 2024: 83.3% from 347 flights
- December 2024: 64.0% from 384 flights
- January 2025: 68.7% from 335 flights
- February 2025: 71.6% from 316 flights
- March 2025: 69.9% from 390 flights
- April 2025: 82.1% from 370 flights
- May 2025: 83.0% from 335 flights
- June 2025: 73.4% from 349 flights
- July 2025: 65.6% from 371 flights
- August 2025: 63.4% from 359 flights
- September 2025: 72.7% from 245 flights
- October 2025: 62.7% from 271 flights
- November 2025: 74.5% from 297 flights
- December 2025: 68.3% from 350 flights
- January 2026: 66.1% from 309 flights
- February 2026: 68.0% from 294 flights
- March 2026: 75.6% from 302 flights
- April 2026: 79.3% from 310 flights
- May 2026: 82.2% from 254 flights
- June 2026: 78.9% from 289 flights
- July 2026: 51.9% from 310 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 70.0% against 74.5% in the 12 months before — declining by 4.5 percentage points.
Data and methodology
Calculated by FlyerIntel from 11,338 JFK → SJU flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed