Route reliability record
SJU→EWR
San Juan to Newark
- Flights
- 2,100
- Period
- July 2025 to June 2026
- Distance
- 1,608 mi
- Carriers
- 4
This route 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 an hour and a half behind schedule. That rests on 2,100 flights, of which United Airlines flew 1,113 at 76.5% on time.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
74.6%
Arrivals under 15 minutes late, of 2,027 completed flights
Avg delay
83 min
Across delayed arrivals only, not all flights
Cancelled
3.14%
National rate is 1.81%
Best carrier
United
76.5% on time across 1,113 flights
These figures cover 2,100 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.
Carrier by carrier
Which airline is most reliable on SJU to EWR
The two carriers here are closely matched: about a point 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,113 | 76.5% | 90 min | 2.70% | B |
| JetBlue Airways | 626 | 75.4% | 80 min | 2.88% | B |
| Frontier Airlinesthin sample | 215 | 69.9% | 67 min | 2.33% | C |
| Spirit Airlinesthin sample | 146 | 63.6% | 79 min | 8.90% | D− |
No carrier stands out. United tops the table at 76.5%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.
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 20 points, against about a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am246 flights84.1%
- 8am–11am38 flights86.5%
- 11am–2pm342 flights68.2%
- 2pm–5pm311 flights66.1%
- 5pm–8pm689 flights74.3%
- 8pm–5am474 flights79.6%
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 86.5% of the time, against 66.1% for the afternoon window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 689 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 24 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.
July is the worst month at 61.7% on time, 24 points below May, the best at 85.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. January was the busiest month here, with 217 flights.
Across the week, Tuesday is the strongest day at 78.6% on time and Sunday the weakest at 68.7%. 10 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 57% of the 43,000 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.
- 57%Late-arriving aircraft
- 27%Carrier
- 15%National Airspace System
- 0%Extreme weather
- 0%Security
57% 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 43,000 reported delay minutes here, that single category outweighs weather by 57 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 42,603 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 86.5% on time here.
Cancellations run at 3.14%, 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 actually 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.
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 70.7% on time across 2,101 flights, 4 points below 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 2,100 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 3.14% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,027 completed flights over 12 months sit behind that.
Common questions
SJU to EWR questions
How often is SJU to EWR 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 25.4% of the 2,100 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on SJU to EWR?
United Airlines leads at 76.5% on time across 1,113 flights. JetBlue Airways is at the other end on 75.4%, a gap of about a point. 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 SJU to EWR?
The 8am–11am departure window is the strongest at 86.5% on time. The 2pm–5pm window is the weakest at 66.1%, 20 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 July delays on SJU to EWR?
July is the weakest month at 61.7% on time, compared with 85.8% in May. Across the year that is 24 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- EWR to SJU — the return legseparate record
- Luis Munoz Marin International (SJU) delay statistics
- Newark Liberty International (EWR) delay statistics
- United Airlines on-time record76.5%
- JetBlue Airways on-time record75.4%
- Frontier Airlines on-time record69.9%
- Why the first flight of the morning is statistically safest
- What a cancellation rate actually tells you (and what it hides)
Direction matters. SJU to EWR and EWR to SJU 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.