Route reliability record

EWR→SJU

Newark to San Juan

Flights: 2,101
Period: July 2025 to June 2026
Distance: 1,608 mi
Carriers: 4

This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 2,101 flights, of which JetBlue Airways flew 628 at 76.4% on time.

The national on-time rate over the same period is 77.6%, so this route runs 7 points behind the country as a whole. Across a thousand flights that is about 69 extra late arrivals.

On time

70.7%

Arrivals under 15 minutes late, of 2,036 completed flights

Avg delay

82 min

Across delayed arrivals only, not all flights

Cancelled

2.95%

National rate is 1.81%

Best carrier

JetBlue

76.4% on time across 628 flights

These figures cover 2,101 flights between July 2025 and June 2026. Beyond the headline rate, 11.5% 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 EWR to SJU

The two carriers here are closely matched: 5 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.

On-time performance by carrier on EWR to SJU
Airline	Flights	On time	Avg delay	Cancelled	Grade
JetBlue Airways	628	76.4%	87 min	3.34%	B−
United Airlines	1,113	71.0%	75 min	2.34%	C
Spirit Airlinesthin sample	146	67.9%	72 min	6.16%	C−
Frontier Airlinesthin sample	214	54.4%	102 min	2.80%	F

JetBlue Airways cancels 3.3% 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 19 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am203 flights81.1%
8am–11am889 flights75.1%
11am–2pm193 flights65.8%
2pm–5pm120 flights71.1%
5pm–8pm354 flights64.6%
8pm–5am342 flights62.3%

Scale runs 55% to 85%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 62.3% on time, against 81.1% 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. The 8am–11am window is the busiest, with 889 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 27 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, November worst

May is the best month on the calendar at 86.6% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. January was the busiest month here, with 214 flights.

Across the week, Tuesday is the strongest day at 76.6% on time and Monday the weakest at 63.5%. 13 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 49,000 reported delay minutes.

Carrier
39%
Late-arriving aircraft
34%
National Airspace System
23%
Extreme weather
4%
Security
0%

The largest share of delay minutes, 39%, 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 19,000 of the 49,000 delay minutes reported here. The split is drawn from 48,612 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 81.1% on time here.

Cancellations run at 2.95%, against 1.81% nationally. That is roughly 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 actually costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.5% 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 1,608 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 74.6% on time across 2,100 flights, 4 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 4 points of difference.

The sample behind these figures is 2,101 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 2.95% 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. 2,036 completed flights over 12 months sit behind that.

Common questions

EWR to SJU questions

How often is EWR to SJU delayed?

Roughly one flight in three arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 29.3% of the 2,101 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on EWR to SJU?

JetBlue Airways leads at 76.4% on time across 628 flights. United Airlines is at the other end on 71.0%, a gap of 5 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 EWR to SJU?

The 5am–8am departure window is the strongest at 81.1% on time. The 8pm–5am window is the weakest at 62.3%, 19 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 November delays on EWR to SJU?

November is the weakest month at 59.3% on time, compared with 86.6% in May. Across the year that is 27 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. EWR to SJU and SJU to EWR 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, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures