Flight number record
B6 734
JetBlue Airways · San Francisco to Boston
- Route
- SFO → BOS
- Departs
- 20:44
- Flights
- 346
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s B6 734, check with JetBlue Airways.
B6 734 sits in the middle of the pack with a C−. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 346 flights, with a median arrival 6 minutes early.
Key figures
On time
74.1%
Arrivals under 15 minutes late, of 332 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
3.76%
National rate is 1.89%
1 hour+ late
11.4%
National rate is 8.3%
These figures cover 346 flights between September 2025 and August 2026. Beyond the headline rate, 11.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Schedule
When B6 734 flies
B6 734 flies SFO to BOS without a single fixed slot. Its most common scheduled departure was 20:44, used on 52 of 346 flights, with 15:18 (48 flights) and 14:00 (37 flights) next.
- Departs 20:4452 flights15.0%
- Departs 15:1848 flights13.9%
- Departs 14:0037 flights10.7%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 20:44 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and B6 734 runs 4 points better at 74.1%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
B6 734 next to SFO to BOS
Every carrier on SFO to BOS combined arrived on time 74.5% of the time across 4,815 flights, so B6 734 is about level with it. JetBlue flew 1,806 flights on the same city pair under all its flight numbers, including this one, and those ran 71.5% on time. Across its whole network JetBlue Airways managed 71.3%, which this flight beats by 3 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| B6 734thin sample | 346 | 74.1% | 75 min | 3.76% | C− |
| All JetBlue Airways on SFO–BOS | 1,806 | 71.5% | 78 min | 2.77% | C |
| All carriers on SFO–BOS | 4,815 | 74.5% | 74 min | 1.81% | C |
| JetBlue Airways, whole network | 240,615 | 71.3% | 77 min | 3.56% | C− |
Across the year
B6 734 quarter by quarter
B6 734 did not run the same all year. Its best quarter was Jan–Mar 2026 at 83.7% on time and its weakest Jul–Sep 2026 at 50.0%, a swing of 34 points on roughly 87 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 202518 flights—
- Oct–Dec 202587 flights75.9%
- Jan–Mar 202690 flights83.7%
- Apr–Jun 202689 flights78.2%
- Jul–Sep 202662 flights50.0%
Scale runs 40% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, B6 734 did best on Saturday at 85.4% on time and worst on Thursday at 62.0%. Each day rests on about 49 flights, so a gap of 23 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late B6 734 runs when it is late
B6 734 often beats the schedule: 120 of 332 completed flights, 36%, arrived 15 minutes or more early. The 86 late arrivals split 27 under half an hour, 21 between 30 and 60 minutes, and 38 an hour or more.
- 15+ min early120 flights36.1%
- Within 15 min126 flights38.0%
- 15–29 min late27 flights8.1%
- 30–59 min late21 flights6.3%
- 1–2 hours late24 flights7.2%
- 2+ hours late14 flights4.2%
Scale runs 0% to 100%.
Share of 332 completed flights by arrival against schedule.
13 of 88 late departures made up the time and arrived on time, 15% of them. 11 flights left on time and still arrived late.
The worst days
Worst days for B6 734
The latest arrival of the period was on 24 February 2026, 16 hours 35 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On three of the five worst days the largest share was filed as a late-arriving aircraft.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 24 February 2026 | 16 hours 35 minutes | Carrier |
| 22 July 2026 | 3 hours 20 minutes | Late-arriving aircraft |
| 30 January 2026 | 3 hours 6 minutes | Late-arriving aircraft |
| 28 March 2026 | 3 hours 6 minutes | Late-arriving aircraft |
| 7 July 2026 | 3 hours 5 minutes | Carrier |
Delay causes
Why B6 734 runs late
Late-arriving aircraft accounts for 61% of the 6,467 delay minutes carriers reported here, and the remaining four split what is left.
- 61%Late-arriving aircraft
- 24%Carrier
- 15%National Airspace System
- 0%Security
61% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 6,467 reported delay minutes here, that single category outweighs weather by 61 to one. The split is drawn from 6,467 delay minutes reported on B6 734.
Cancellations run at 3.76%, against 1.89% nationally. That is about one flight in 25 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
11.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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 346 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. 346 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: 3.76% of its 346 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.
Related
Where to go next
- SFO to BOS, every carrier and departure
- BOS to SFO, the return direction
- Delta Air Lines 400 on the same route88.5%
- United Airlines 1665 on the same route83.7%
- JetBlue Airways 1734 on the same route66.2%
- United Airlines 1372 on the same route74.3%
- United Airlines 2647 on the same route81.8%
- United Airlines 2356 on the same route63.0%
- San Francisco International (SFO) delay statistics
- Boston Logan International (BOS) delay statistics
- JetBlue Airways on-time record
- Every JetBlue Airways flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.