Carrier route record
B6SFO→BOS
JetBlue Airways · San Francisco to Boston
- Flights
- 1,674
- Period
- July 2025 to June 2026
- Share of route
- 36%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with JetBlue Airways.
JetBlue on SFO to BOS sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 1,674 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,866 at 79.1% on time.
The US average over the same twelve months is 77.6%, so there is little to separate JetBlue on SFO to BOS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
75.4%
Arrivals under 15 minutes late, of 1,643 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
1.79%
National rate is 1.81%
Whole route
76.9%
Every carrier on SFO to BOS, 4,674 flights
These figures cover 1,674 flights between July 2025 and June 2026. Beyond the headline rate, 10.3% 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.
Carrier by carrier
JetBlue against every carrier on SFO to BOS
JetBlue flew 1,674 of the 4,674 flights on SFO to BOS, about 36% of it. Its 75.4% on time is 2 points worse than the route as a whole, which runs 76.9%. Ranked by on-time rate it is number three of five carriers on the route, where the range runs from United at 79.1% to Southwest at 0.0%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,866 | 79.1% | 73 min | 1.02% | B |
| Alaska Airlinesthin sample | 234 | 77.3% | 57 min | 0.43% | B+ |
| JetBlue Airways (this page) | 1,674 | 75.4% | 76 min | 1.79% | B |
| Delta Air Lines | 899 | 75.1% | 73 min | 1.45% | B |
| Southwest Airlinesthin sample | 1 | 0.0% | 49 min | 0.00% | F+ |
No carrier stands out. United tops the table at 79.1%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
JetBlue flight numbers on SFO to BOS
Departure window
When JetBlue runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 13 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am179 flights84.9%
- 8am–11am300 flights75.3%
- 11am–2pm404 flights72.2%
- 2pm–5pm366 flights76.0%
- 5pm–8pm1 flights—
- 8pm–5am424 flights73.8%
Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 72.2% on time against 84.9% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8pm–5am window is the busiest, with 424 flights scheduled in it.
Across the year
JetBlue on SFO to BOS through the year
June is the worst month at 61.2% on time, 28 points below August, the best at 89.4%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. June was the busiest month here, with 203 flights.
Across the week, Saturday is the strongest day at 82.9% on time and Thursday the weakest at 65.3%. 18 points is a smaller lever than departure hour, but it is free.
Delay causes
Why JetBlue runs late on this route
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 31,000 reported delay minutes.
- 41%Late-arriving aircraft
- 34%National Airspace System
- 23%Carrier
- 2%Extreme weather
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 31,000 reported delay minutes here, that single category outweighs weather by 25 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 30,810 reported delay minutes.
34% 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 10,000 minutes out of 31,000, against a national NAS share of 21%.
Cancellations sit at 1.79% against a national 1.81%, which is ordinary. Diversions add another 0.06%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.3% 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.
The return leg is a different operation and performs like one: it runs 70.5% on time across 1,676 flights, 5 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 5 points of difference.
The sample behind these figures is 1,674 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking JetBlue on SFO to BOS
Put together: the calendar is the biggest lever here, not the carrier or the hour. August runs 89.4% on time and June 61.2%, a swing of 28 points. If the dates move at all, move them out of June before you think about anything else. 1,643 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to BOS, every carrier
- JetBlue on BOS to SFO, the return leg
- United Airlines on SFO to BOS79.1%
- Alaska Airlines on SFO to BOS77.3%
- Delta Air Lines on SFO to BOS75.1%
- JetBlue Airways network-wide record
- San Francisco International (SFO) delay statistics
- Boston Logan International (BOS) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
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.