Flight number record
B6 503
JetBlue Airways · New York to San Juan
- Route
- JFK → SJU
- Departs
- 10:00
- Flights
- 357
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s B6 503, check with JetBlue Airways.
B6 503 sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 357 flights, with a median arrival 4 minutes early.
The national on-time rate over the same period is 77.3%, so B6 503 runs 5 points behind the country as a whole. Across a thousand flights that is about 52 extra late arrivals.
Key figures
On time
72.1%
Arrivals under 15 minutes late, of 337 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
5.60%
National rate is 1.89%
1 hour+ late
11.6%
National rate is 8.3%
These figures cover 357 flights between September 2025 and August 2026. Beyond the headline rate, 11.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When B6 503 flies
B6 503 flies JFK to SJU without a single fixed slot. Its most common scheduled departure was 10:00, used on 58 of 357 flights, with 11:00 (39 flights) and 14:30 (37 flights) next.
- Departs 10:0058 flights16.2%
- Departs 11:0039 flights10.9%
- Departs 14:3037 flights10.4%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 10:00 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and B6 503 runs 12 points worse at 72.1%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
B6 503 next to JFK to SJU
Every carrier on JFK to SJU combined arrived on time 70.2% of the time across 3,554 flights, so B6 503 is 2 points ahead of it. JetBlue flew 2,245 flights on the same city pair under all its flight numbers, including this one, and those ran 67.7% on time. Across its whole network JetBlue Airways managed 71.3%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| B6 503thin sample | 357 | 72.1% | 76 min | 5.60% | C− |
| All JetBlue Airways on JFK–SJU | 2,245 | 67.7% | 78 min | 4.14% | C− |
| All carriers on JFK–SJU | 3,554 | 70.2% | 78 min | 3.57% | C− |
| JetBlue Airways, whole network | 240,615 | 71.3% | 77 min | 3.56% | C− |
Across the year
B6 503 quarter by quarter
B6 503 did not run the same all year. Its best quarter was Apr–Jun 2026 at 84.4% on time and its weakest Jul–Sep 2026 at 61.2%, a swing of 23 points on roughly 71 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights76.7%
- Oct–Dec 202587 flights65.9%
- Jan–Mar 202689 flights69.9%
- Apr–Jun 202690 flights84.4%
- Jul–Sep 202661 flights61.2%
Scale runs 55% to 90%.
By weekday, B6 503 did best on Tuesday at 81.2% on time and worst on Thursday at 59.6%. Each day rests on about 51 flights, so a gap of 22 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late B6 503 runs when it is late
B6 503 often beats the schedule: 100 of 337 completed flights, 30%, arrived 15 minutes or more early. The 94 late arrivals split 27 under half an hour, 28 between 30 and 60 minutes, and 39 an hour or more.
- 15+ min early100 flights29.7%
- Within 15 min143 flights42.4%
- 15–29 min late27 flights8.0%
- 30–59 min late28 flights8.3%
- 1–2 hours late18 flights5.3%
- 2+ hours late21 flights6.2%
Scale runs 0% to 100%.
Share of 337 completed flights by arrival against schedule.
A late pushback is often recovered here: of 118 departures that left 15 minutes late or more, 39 still arrived on time. 15 flights left on time and still arrived late.
The worst days
Worst days for B6 503
The latest arrival of the period was on 14 December 2025, 5 hours 42 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in December 2025.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 14 December 2025 | 5 hours 42 minutes | Carrier |
| 12 October 2025 | 4 hours 53 minutes | Carrier |
| 29 November 2025 | 4 hours 51 minutes | Late-arriving aircraft |
| 15 December 2025 | 4 hours 39 minutes | Late-arriving aircraft |
| 26 December 2025 | 3 hours 52 minutes | Late-arriving aircraft |
Delay causes
Why B6 503 runs late
Late-arriving aircraft accounts for 47% of the 7,152 delay minutes carriers reported here, and the remaining four split what is left.
- 47%Late-arriving aircraft
- 34%Carrier
- 18%National Airspace System
- 1%Extreme weather
47% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 7,152 reported delay minutes here, that single category outweighs weather by 38 to one. The split is drawn from 7,152 delay minutes reported on B6 503.
Cancellations run at 5.60%, against 1.89% nationally. That is roughly one flight in twenty 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 routes
What a delay on this flight costs
11.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
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.
Every one of the 357 flights under B6 503 in the data flew JFK to SJU. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 357 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking B6 503
For a booking, the cancellation rate is the figure to plan around on B6 503: 5.60% of its 357 scheduled flights did not operate. A late arrival costs a little over an hour, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- JFK to SJU, every carrier and departure
- SJU to JFK, the return direction
- Delta Air Lines 1961 on the same route83.6%
- Delta Air Lines 1859 on the same route67.4%
- Delta Air Lines 1966 on the same route80.5%
- JetBlue Airways 803 on the same route62.2%
- JetBlue Airways 1603 on the same route75.6%
- John F. Kennedy International (JFK) delay statistics
- Luis Munoz Marin International (SJU) delay statistics
- JetBlue Airways on-time record
- Every JetBlue Airways flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
A flight number here means JetBlue Airways’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.