Flight number record

B6 640

JetBlue Airways · Cleveland to Boston

Route: CLE → BOS
Departs: 14:41
Flights: 279
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s B6 640, check with JetBlue Airways.

B6 640 draws a D−. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 279 flights, with a median arrival 3 minutes early.

The national on-time rate over the same period is 77.6%, so B6 640 runs 16 points behind the country as a whole. Across a thousand flights that is about 157 extra late arrivals.

On time

61.9%

Arrivals under 15 minutes late, of 270 completed flights

Avg delay

72 min

Across delayed arrivals only, not all flights

Cancelled

3.23%

National rate is 1.81%

1 hour+ late

17.4%

National rate is 8.1%

These figures cover 279 flights between July 2025 and June 2026. Beyond the headline rate, 17.4% 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 640 flies

B6 640 flies CLE to BOS without a single fixed slot. Its most common scheduled departure was 14:41, used on 46 of 279 flights. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 14:4146 flights16.5%

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 14:41 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and B6 640 runs 11 points worse at 61.9%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

B6 640 next to CLE to BOS

Every carrier on CLE to BOS combined arrived on time 78.8% of the time across 1,682 flights, so B6 640 is 17 points behind it. JetBlue flew 726 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 72.7%, which this flight trails by 11 points.

B6 640 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
B6 640thin sample	279	61.9%	72 min	3.23%	D−
All JetBlue Airways on CLE–BOS	726	71.5%	75 min	2.34%	C
All carriers on CLE–BOS	1,682	78.8%	72 min	2.26%	B
JetBlue Airways, whole network	234,468	72.7%	76 min	2.56%	C

Across the year

B6 640 quarter by quarter

B6 640 did not run the same all year. Its best quarter was Apr–Jun 2026 at 70.4% on time and its weakest Jul–Sep 2025 at 46.2%, a swing of 24 points on roughly 93 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 202584 flights46.2%
Oct–Dec 202589 flights64.0%
Jan–Mar 202625 flights—
Apr–Jun 202681 flights70.4%

Scale runs 40% to 75%. Rows with fewer than 30 flights show a dash.

By weekday, B6 640 did best on Saturday at 82.2% on time and worst on Sunday at 46.3%. Each day rests on about 40 flights, so a gap of 36 points is worth noticing but could still narrow in another year.

Delay causes

Why B6 640 runs late

One category carries most of the weight here. National Airspace System accounts for 48% of the 7,434 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
48%
Late-arriving aircraft
40%
Carrier
11%
Extreme weather
0%
Security
0%

40% 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 7,434 reported delay minutes here, that single category outweighs weather by 40 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 7,434 delay minutes reported on B6 640.

Cancellations run at 3.23%, against 1.81% nationally. That is about one flight in 30 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. 17.4% 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 563 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 279 flights under B6 640 in the data flew CLE 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. 279 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 640

For a booking, the cancellation rate is the figure to plan around on B6 640: 3.23% of its 279 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