Carrier route record

DLJFK→BOS

Delta Air Lines · New York to Boston

Flights: 368
Period: July 2025 to June 2026
Share of route: 6%
Carriers: 3

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.

Delta on JFK to BOS sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 368 flights. The strongest carrier on the route with a full sample, Republic Airways, flew 2,916 at 77.8% on time.

The national on-time rate over the same period is 77.6%, so Delta on JFK to BOS runs 9 points behind the country as a whole. Across a thousand flights that is about 88 extra late arrivals.

On time

68.8%

Arrivals under 15 minutes late, of 356 completed flights

Avg delay

93 min

Across delayed arrivals only, not all flights

Cancelled

3.26%

National rate is 1.81%

Whole route

73.7%

Every carrier on JFK to BOS, 5,744 flights

These figures cover 368 flights between July 2025 and June 2026. Beyond the headline rate, 16.3% 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

Delta against every carrier on JFK to BOS

Delta flew 368 of the 5,744 flights on JFK to BOS, about 6% of it. Its 68.8% on time is 5 points worse than the route as a whole, which runs 73.7%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from Republic at 77.8% to Delta at 68.8%.

The choice of carrier is not cosmetic here. Republic Airways arrives on time 77.8% of the time; JetBlue Airways manages 69.7%. Sample sizes sit next to every figure, because a two-point gap across 2,460 flights means less than a ten-point one.

On-time performance by carrier on JFK to BOS
Airline	Flights	On time	Avg delay	Cancelled	Grade
Republic Airways	2,916	77.8%	74 min	4.39%	B−
JetBlue Airways	2,460	69.7%	79 min	4.07%	C−
Delta Air Lines (this page)	368	68.8%	93 min	3.26%	C−

Republic Airways cancels 4.4% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

Flight by flight

Delta flight numbers on JFK to BOS

DL 263921:0068.2% · 349 flights

Departure window

When Delta runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 368 flights.

The overnight block holds up unusually well at 68.2% on time across 348 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8pm–5am window is the busiest, with 348 flights scheduled in it.

Across the year

Delta on JFK to BOS through the year

Darker means more delays. Figures are on-time percentages.March best, October worst

Delays peak in October, when the on-time rate falls to 63.3%. March is the strongest month at 80.0%. Moving a flexible trip across that boundary buys 17 points. April was the busiest month here, with 32 flights.

Across the week, Friday is the strongest day at 75.0% on time and Thursday the weakest at 58.0%. 17 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta 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 10,000 reported delay minutes.

Late-arriving aircraft
41%
Carrier
40%
National Airspace System
18%
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 10,000 reported delay minutes here, that single category outweighs weather by 31 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 10,332 reported delay minutes.

The largest share of delay minutes, 40%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 4,113 of the 10,000 delay minutes reported here.

Cancellations run at 3.26%, 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 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. 16.3% 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 187 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8pm–5am window matters as much as it does.

The return leg is a different operation and performs like one: it runs 90.8% on time across 368 flights, 22 points above 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 22 points of difference.

One caution: this is a thin sample. 368 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 Delta on JFK to BOS

Put together: the delay figures matter less here than the 3.26% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 8pm–5am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 356 completed flights over 12 months sit behind that.

Where to go next

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