Route reliability record

JFK→BOS

New York to Boston

Flights: 5,761
Period: June 2025 to May 2026
Distance: 187 mi
Carriers: 3

This route carries a cancellation problem, not just a delay problem: 4.2% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, close to three flights in four arrive on time, worth a C− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 5,761 flights, of which Republic Airways flew 2,916 at 77.6% on time.

Republic Airways is the most reliable of the three carriers covered here at 77.6% on time across 2,916 flights.

On time

73.2%

Arrivals under 15 minutes late, of 5,519 completed flights

Avg delay

78 min

Across delayed arrivals only, not all flights

Cancelled

4.18%

National rate is 1.80%

Best carrier

Republic

77.6% on time across 2,916 flights

These figures cover 5,761 flights between June 2025 and May 2026. Beyond the headline rate, 12.3% 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

Which airline is most reliable on JFK to BOS

The choice of carrier is not cosmetic here. Republic Airways arrives on time 77.6% of the time; Delta Air Lines manages 66.4%. Sample sizes sit next to every figure, because a two-point gap across 368 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	77.6%	73 min	4.63%	B−
JetBlue Airways	2,477	69.1%	78 min	3.84%	C−
Delta Air Lines	368	66.4%	102 min	2.99%	C

Republic Airways cancels 4.6% 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.

Departure window

The best time of day to leave

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 30 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am823 flights90.3%
8am–11am1,105 flights85.9%
11am–2pm525 flights76.0%
2pm–5pm1,135 flights64.5%
5pm–8pm931 flights60.6%
8pm–5am1,242 flights65.8%

Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 60.6% on time, against 90.3% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in.

Across the year

When delays peak on this route

This route's year swings by 17 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

Darker means more delays. Figures are on-time percentages.May best, September worst

May is the best month on the calendar at 83.0% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back.

Across the week, Saturday is the strongest day at 79.2% on time and Sunday the weakest at 68.0%. 11 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

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 115,000 reported delay minutes.

Late-arriving aircraft
40%
National Airspace System
35%
Carrier
23%
Extreme weather
1%
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 115,000 reported delay minutes here, that single category outweighs weather by 29 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.

35% 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 40,000 minutes out of 115,000, against a national NAS share of 21%.

Cancellations run at 4.18%, against 1.80% 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 stage length

What a delay here actually costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 12.3% of arrivals land a full hour or more behind schedule, against 8.2% 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 5am–8am window matters as much as it does.

The return leg runs 75.0% on time across 5,756 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 5,761 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 this route

Put together: the delay figures matter less here than the 4.18% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic.

Common questions

JFK to BOS questions

How often is JFK to BOS delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 26.8% of the 5,761 flights in this analysis, against 22.6% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on JFK to BOS?

Republic Airways leads at 77.6% on time across 2,916 flights. Delta Air Lines is at the other end on 66.4%, a gap of 11 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on JFK to BOS?

The 5am–8am departure window is the strongest at 90.3% on time. The 5pm–8pm window is the weakest at 60.6%, 30 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are September delays on JFK to BOS?

September is the weakest month at 66.2% on time, compared with 83.0% in May. Across the year that is 17 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. JFK to BOS and BOS to JFK are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.

Key figures