Flight number record

B6 904

JetBlue Airways · San Juan to New York

Route: SJU → JFK
Departs: 10:35
Flights: 309
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s B6 904, check with JetBlue Airways.

B6 904 sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 309 flights, with a median arrival 5 minutes early.

The national on-time rate over the same period is 77.6%, so B6 904 runs 4 points behind the country as a whole. Across a thousand flights that is about 44 extra late arrivals.

On time

73.2%

Arrivals under 15 minutes late, of 302 completed flights

Avg delay

72 min

Across delayed arrivals only, not all flights

Cancelled

2.27%

National rate is 1.81%

1 hour+ late

7.9%

National rate is 8.1%

These figures cover 309 flights between July 2025 and June 2026. The median arrival is 5 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

Schedule

When B6 904 flies

B6 904 flies SJU to JFK without a single fixed slot. Its most common scheduled departure was 10:35, used on 60 of 309 flights, with 13:25 (42 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 10:3560 flights19.4%
Departs 13:2542 flights13.6%

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 10:35 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and B6 904 runs 11 points worse at 73.2%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

B6 904 next to SJU to JFK

Every carrier on SJU to JFK combined arrived on time 79.3% of the time across 3,657 flights, so B6 904 is 6 points behind it. JetBlue flew 2,237 flights on the same city pair under all its flight numbers, including this one, and those ran 75.0% on time. Across its whole network JetBlue Airways managed 72.7%, close to this flight's figure.

B6 904 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
B6 904thin sample	309	73.2%	72 min	2.27%	C
All JetBlue Airways on SJU–JFK	2,237	75.0%	78 min	3.22%	B−
All carriers on SJU–JFK	3,657	79.3%	77 min	2.68%	B
JetBlue Airways, whole network	234,468	72.7%	76 min	2.56%	C

Across the year

B6 904 quarter by quarter

B6 904 did not run the same all year. Its best quarter was Apr–Jun 2026 at 88.5% on time and its weakest Jul–Sep 2025 at 63.3%, a swing of 25 points on roughly 77 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 flights63.3%
Oct–Dec 202575 flights73.0%
Jan–Mar 202690 flights74.4%
Apr–Jun 202652 flights88.5%

Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, B6 904 did best on Wednesday at 82.2% on time and worst on Thursday at 63.6%. Each day rests on about 44 flights, so a gap of 19 points is worth noticing but could still narrow in another year.

Delay causes

Why B6 904 runs late

One category carries most of the weight here. Carrier accounts for 48% of the 5,796 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Carrier
48%
Late-arriving aircraft
37%
National Airspace System
14%
Extreme weather
0%

37% 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 5,796 reported delay minutes here, that single category outweighs weather by 37 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 5,796 delay minutes reported on B6 904.

Cancellations sit at 2.27% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and routes

What a delay on this flight costs

7.9% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, 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.

Every one of the 309 flights under B6 904 in the data flew SJU to JFK. 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. 309 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 904

For a booking, B6 904 is one of the weaker ways to fly SJU to JFK: 6 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.

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