Flight number record

B6 513

JetBlue Airways · Islip to Fort Lauderdale

Route: ISP → FLL
Departs: 12:25
Flights: 342
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s B6 513, check with JetBlue Airways.

B6 513 sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 342 flights, with a median arrival 2 minutes early.

The national on-time rate over the same period is 77.6%, so B6 513 runs 6 points behind the country as a whole. Across a thousand flights that is about 63 extra late arrivals.

On time

71.3%

Arrivals under 15 minutes late, of 334 completed flights

Avg delay

83 min

Across delayed arrivals only, not all flights

Cancelled

1.46%

National rate is 1.81%

1 hour+ late

9.6%

National rate is 8.1%

These figures cover 342 flights between July 2025 and June 2026. Beyond the headline rate, 9.6% 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 513 flies

B6 513 flies ISP to FLL without a single fixed slot. Its most common scheduled departure was 12:25, used on 53 of 342 flights. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 12:2553 flights15.5%

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 12:25 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and B6 513 runs 8 points worse at 71.3%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

B6 513 next to ISP to FLL

Every carrier on ISP to FLL combined arrived on time 68.6% of the time across 392 flights, so B6 513 is 3 points ahead of it. Across its whole network JetBlue Airways managed 72.7%, close to this flight's figure.

B6 513 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
B6 513thin sample	342	71.3%	83 min	1.46%	C
All JetBlue Airways on ISP–FLL	370	70.9%	81 min	1.62%	C
All carriers on ISP–FLL	392	68.6%	77 min	1.79%	C
JetBlue Airways, whole network	234,468	72.7%	76 min	2.56%	C

Across the year

B6 513 quarter by quarter

B6 513 did not run the same all year. Its best quarter was Apr–Jun 2026 at 81.1% on time and its weakest Jan–Mar 2026 at 65.5%, a swing of 16 points on roughly 86 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 202580 flights71.8%
Oct–Dec 202582 flights65.9%
Jan–Mar 202689 flights65.5%
Apr–Jun 202691 flights81.1%

Scale runs 55% to 85%. Rows with fewer than 30 flights show a dash.

By weekday, B6 513 did best on Wednesday at 90.4% on time and worst on Sunday at 59.1%. Each day rests on about 49 flights, so a gap of 31 points is worth noticing but could still narrow in another year.

Delay causes

Why B6 513 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 7,933 reported delay minutes.

Late-arriving aircraft
41%
Carrier
39%
National Airspace System
19%
Extreme weather
0%

41% 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 7,933 reported delay minutes here, that single category outweighs weather by 41 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 7,933 delay minutes reported on B6 513.

Cancellations sit at 1.46% against a national 1.81%, which is ordinary. Diversions add another 0.88%.

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. 9.6% 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.

The 1,092 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.

Every one of the 342 flights under B6 513 in the data flew ISP to FLL. 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. 342 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 513

For a booking, read B6 513 as 71.3% on time with 1.46% cancelled over 342 flights. Those are rates from the past twelve months, not a forecast for any particular day.

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