Flight number record

B6 861

JetBlue Airways · Boston to San Juan

Route: BOS → SJU
Departs: 08:00
Flights: 364
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s B6 861, check with JetBlue Airways.

B6 861 lands a B, 2 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 364 flights, with a median arrival 9 minutes early.

On time

79.8%

Arrivals under 15 minutes late, of 352 completed flights

Avg delay

55 min

Across delayed arrivals only, not all flights

Cancelled

2.75%

National rate is 1.81%

1 hour+ late

6.0%

National rate is 8.1%

These figures cover 364 flights between July 2025 and June 2026. The median arrival is 9 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 861 flies

B6 861 flies BOS to SJU without a single fixed slot. Its most common scheduled departure was 08:00, used on 148 of 364 flights, with 05:01 (78 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 08:00148 flights40.7%
Departs 05:0178 flights21.4%

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 08:00 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and B6 861 runs 4 points worse at 79.8%. 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 861 next to BOS to SJU

Every carrier on BOS to SJU combined arrived on time 69.0% of the time across 1,819 flights, so B6 861 is 11 points ahead of it. JetBlue flew 1,232 flights on the same city pair under all its flight numbers, including this one, and those ran 69.2% on time. Across its whole network JetBlue Airways managed 72.7%, which this flight beats by 7 points.

B6 861 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
B6 861thin sample	364	79.8%	55 min	2.75%	B
All JetBlue Airways on BOS–SJU	1,232	69.2%	71 min	2.44%	C
All carriers on BOS–SJU	1,819	69.0%	74 min	2.69%	C
JetBlue Airways, whole network	234,468	72.7%	76 min	2.56%	C

Across the year

B6 861 quarter by quarter

B6 861 did not run the same all year. Its best quarter was Jul–Sep 2025 at 84.4% on time and its weakest Jan–Mar 2026 at 74.4%, a swing of 10 points on roughly 91 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 flights84.4%
Oct–Dec 202591 flights82.0%
Jan–Mar 202690 flights74.4%
Apr–Jun 202691 flights78.0%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, B6 861 did best on Tuesday at 88.0% on time and worst on Thursday at 73.1%. Each day rests on about 52 flights, so a gap of 15 points is worth noticing but could still narrow in another year.

Delay causes

Why B6 861 runs late

One category carries most of the weight here. National Airspace System accounts for 58% of the 3,910 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.

National Airspace System
58%
Carrier
25%
Late-arriving aircraft
16%
Extreme weather
1%

58% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 2,279 minutes out of 3,910, against a national NAS share of 21%. The split is drawn from 3,910 delay minutes reported on B6 861.

Cancellations run at 2.75%, against 1.81% nationally. That is roughly 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

6.0% 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 about an hour, which a normal layover absorbs.

At 1,674 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 364 flights under B6 861 in the data flew BOS 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. 364 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 861

For a booking, the cancellation rate is the figure to plan around on B6 861: 2.75% of its 364 scheduled flights did not operate. A late arrival costs about an hour, 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