Flight number record

B6 312

JetBlue Airways · Chicago to Boston

Route: ORD → BOS
Departs: 08:40
Flights: 335
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s B6 312, check with JetBlue Airways.

B6 312 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 77.6%. The late ones land a little over an hour behind schedule. That rests on 335 flights, with a median arrival 10 minutes early.

On time

74.2%

Arrivals under 15 minutes late, of 329 completed flights

Avg delay

76 min

Across delayed arrivals only, not all flights

Cancelled

1.79%

National rate is 1.81%

1 hour+ late

9.7%

National rate is 8.1%

These figures cover 335 flights between July 2025 and June 2026. Beyond the headline rate, 9.7% 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 312 flies

B6 312 flies ORD to BOS without a single fixed slot. Its most common scheduled departure was 08:40, used on 55 of 335 flights. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 08:4055 flights16.4%

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 08:40 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and B6 312 runs 10 points worse at 74.2%. 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 312 next to ORD to BOS

Every carrier on ORD to BOS combined arrived on time 67.6% of the time across 7,642 flights, so B6 312 is 7 points ahead of it. JetBlue flew 534 flights on the same city pair under all its flight numbers, including this one, and those ran 73.5% on time. Across its whole network JetBlue Airways managed 72.7%, which this flight beats by 2 points.

B6 312 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
B6 312thin sample	335	74.2%	76 min	1.79%	C
All JetBlue Airways on ORD–BOS	534	73.5%	83 min	2.62%	C
All carriers on ORD–BOS	7,642	67.6%	78 min	2.79%	C
JetBlue Airways, whole network	234,468	72.7%	76 min	2.56%	C

Across the year

B6 312 quarter by quarter

B6 312 did not run the same all year. Its best quarter was Apr–Jun 2026 at 85.9% on time and its weakest Oct–Dec 2025 at 63.0%, a swing of 23 points on roughly 84 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 flights81.1%
Oct–Dec 202573 flights63.0%
Jan–Mar 202685 flights64.2%
Apr–Jun 202685 flights85.9%

Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, B6 312 did best on Wednesday at 83.7% on time and worst on Monday at 64.4%. Each day rests on about 48 flights, so a gap of 19 points is worth noticing but could still narrow in another year.

Delay causes

Why B6 312 runs late

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 6,474 reported delay minutes.

Late-arriving aircraft
41%
National Airspace System
34%
Carrier
24%
Extreme weather
1%

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 6,474 reported delay minutes here, that single category outweighs weather by 41 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 6,474 delay minutes reported on B6 312.

Cancellations sit at 1.79% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

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. 9.7% 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.

The 867 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

Every one of the 335 flights under B6 312 in the data flew ORD 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. 335 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 312

For a booking, read B6 312 as 74.2% on time with 1.79% cancelled over 335 flights. Those are rates from the past twelve months, not a forecast for any particular day.

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