Flight number record

B6 734

JetBlue Airways · San Francisco to Boston

Route: SFO → BOS
Departs: 15:15
Flights: 337
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s B6 734, check with JetBlue Airways.

B6 734 lands a B, level with the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 337 flights, with a median arrival 8 minutes early.

On time

78.3%

Arrivals under 15 minutes late, of 327 completed flights

Avg delay

76 min

Across delayed arrivals only, not all flights

Cancelled

2.67%

National rate is 1.81%

1 hour+ late

9.5%

National rate is 8.1%

These figures cover 337 flights between July 2025 and June 2026. Beyond the headline rate, 9.5% 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 734 flies

B6 734 flies SFO to BOS without a single fixed slot. Its most common scheduled departure was 15:15, used on 55 of 337 flights, with 20:44 (52 flights) and 14:00 (37 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 15:1555 flights16.3%
Departs 20:4452 flights15.4%
Departs 14:0037 flights11.0%

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 15:15 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and B6 734 runs 6 points better at 78.3%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

B6 734 next to SFO to BOS

Every carrier on SFO to BOS combined arrived on time 76.9% of the time across 4,674 flights, so B6 734 is about level with it. JetBlue flew 1,674 flights on the same city pair under all its flight numbers, including this one, and those ran 75.4% on time. Across its whole network JetBlue Airways managed 72.7%, which this flight beats by 6 points.

B6 734 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
B6 734thin sample	337	78.3%	76 min	2.67%	B
All JetBlue Airways on SFO–BOS	1,674	75.4%	76 min	1.79%	B
All carriers on SFO–BOS	4,674	76.9%	74 min	1.35%	B
JetBlue Airways, whole network	234,468	72.7%	76 min	2.56%	C

Across the year

B6 734 quarter by quarter

Quarter by quarter B6 734 held fairly steady: 74.6% in Jul–Sep 2025, 75.9% in Oct–Dec 2025, 83.7% in Jan–Mar 2026 and 78.2% in Apr–Jun 2026. A spread of 9 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202571 flights74.6%
Oct–Dec 202587 flights75.9%
Jan–Mar 202690 flights83.7%
Apr–Jun 202689 flights78.2%

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

By weekday, B6 734 did best on Wednesday at 85.1% on time and worst on Thursday at 68.0%. Each day rests on about 48 flights, so a gap of 17 points is worth noticing but could still narrow in another year.

Delay causes

Why B6 734 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 60% of the 5,386 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.

Late-arriving aircraft
60%
Carrier
25%
National Airspace System
16%

60% 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 5,386 reported delay minutes here, that single category outweighs weather by 60 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 5,386 delay minutes reported on B6 734.

Cancellations run at 2.67%, 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. 9.5% 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 2,704 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 337 flights under B6 734 in the data flew SFO to BOS. 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. 337 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 734

For a booking, the cancellation rate is the figure to plan around on B6 734: 2.67% of its 337 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.

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