Flight number record

B6 503

JetBlue Airways · New York to San Juan

Route: JFK → SJU
Departs: 11:15
Flights: 358
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 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, 9 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 358 flights, with a median arrival 2 minutes early.

The national on-time rate over the same period is 77.6%, so B6 503 runs 9 points behind the country as a whole. Across a thousand flights that is about 86 extra late arrivals.

On time

69.0%

Arrivals under 15 minutes late, of 348 completed flights

Avg delay

87 min

Across delayed arrivals only, not all flights

Cancelled

2.51%

National rate is 1.81%

1 hour+ late

12.9%

National rate is 8.1%

These figures cover 358 flights between July 2025 and June 2026. Beyond the headline rate, 12.9% 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.

Schedule

When B6 503 flies

B6 503 flies JFK to SJU without a single fixed slot. Its most common scheduled departure was 11:15, used on 60 of 358 flights, with 11:00 (39 flights) and 14:30 (37 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 11:1560 flights16.8%
Departs 11:0039 flights10.9%
Departs 14:3037 flights10.3%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 11:15 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and B6 503 runs 10 points worse at 69.0%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

B6 503 next to JFK to SJU

Every carrier on JFK to SJU combined arrived on time 71.1% of the time across 3,651 flights, so B6 503 is 2 points behind it. JetBlue flew 2,232 flights on the same city pair under all its flight numbers, including this one, and those ran 69.5% on time. Across its whole network JetBlue Airways managed 72.7%, which this flight trails by 4 points.

B6 503 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
B6 503thin sample	358	69.0%	87 min	2.51%	C
All JetBlue Airways on JFK–SJU	2,232	69.5%	74 min	2.91%	C
All carriers on JFK–SJU	3,651	71.1%	74 min	2.63%	C
JetBlue Airways, whole network	234,468	72.7%	76 min	2.56%	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 2025 at 55.6%, a swing of 29 points on roughly 90 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 202592 flights55.6%
Oct–Dec 202587 flights65.9%
Jan–Mar 202689 flights69.9%
Apr–Jun 202690 flights84.4%

Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, B6 503 did best on Tuesday at 76.0% on time and worst on Thursday at 51.9%. Each day rests on about 51 flights, so a gap of 24 points is worth noticing but could still narrow in another year.

Delay causes

Why B6 503 runs late

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 9,430 reported delay minutes.

Carrier
42%
Late-arriving aircraft
40%
National Airspace System
17%
Extreme weather
1%

40% 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 9,430 reported delay minutes here, that single category outweighs weather by 40 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 split is drawn from 9,430 delay minutes reported on B6 503.

Cancellations run at 2.51%, against 1.81% nationally. That is about one flight in 40 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

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 12.9% of arrivals land a full hour or more behind schedule, against 8.1% 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.

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 358 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. 358 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: 2.51% of its 358 scheduled flights did not operate. A late arrival costs an hour and a half, but a cancellation costs the day, so leave a later option open.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures