Carrier route record

F9SJU→EWR

Frontier Airlines · San Juan to Newark

Flights: 215
Period: July 2025 to June 2026
Share of route: 10%
Carriers: 4

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

Frontier on SJU to EWR sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 215 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,113 at 76.5% on time.

The national on-time rate over the same period is 77.6%, so Frontier on SJU to EWR runs 8 points behind the country as a whole. Across a thousand flights that is about 77 extra late arrivals.

On time

69.9%

Arrivals under 15 minutes late, of 209 completed flights

Avg delay

67 min

Across delayed arrivals only, not all flights

Cancelled

2.33%

National rate is 1.81%

Whole route

74.6%

Every carrier on SJU to EWR, 2,100 flights

These figures cover 215 flights between July 2025 and June 2026. Beyond the headline rate, 8.1% 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

Frontier against every carrier on SJU to EWR

Frontier flew 215 of the 2,100 flights on SJU to EWR, about 10% of it. Its 69.9% on time is 5 points worse than the route as a whole, which runs 74.6%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from United at 76.5% to Spirit at 63.6%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

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.

On-time performance by carrier on SJU to EWR
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 Airlines (this page)thin 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

When Frontier runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 16 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–8am81 flights80.0%
8am–11am—
11am–2pm—
2pm–5pm—
5pm–8pm134 flights64.2%
8pm–5am—

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

The 5pm–8pm window is where this operation falls apart: 64.2% on time, against 80.0% 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 5pm–8pm window is the busiest, with 134 flights scheduled in it.

Across the year

Frontier on SJU to EWR through the year

Jul–Sep 202592 flights60.9%
Oct–Dec 202555 flights74.1%
Jan–Mar 202655 flights80.0%
Apr–Jun 202613 flights—

Scale runs 50% to 85%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 69.9% on time across 215 flights.

Frontier on SJU to EWR did not run the same all year. Its best quarter was Jan–Mar 2026 at 80.0% on time and its weakest Jul–Sep 2025 at 60.9%, a swing of 19 points on roughly 72 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.

Across the week, Wednesday is the strongest day at 77.8% on time and Monday the weakest at 67.6%. 10 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Frontier 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 4,229 reported delay minutes.

Late-arriving aircraft
42%
Carrier
33%
National Airspace System
24%
Extreme weather
1%

42% 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 4,229 reported delay minutes here, that single category outweighs weather by 30 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 4,229 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 80.0% on time here.

Cancellations sit at 2.33% against a national 1.81%, which is ordinary. Diversions add another 0.47%.

Connections and stage length

What a delay here costs

8.1% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.

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 54.4% on time across 214 flights, 16 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 16 points of difference.

One caution: this is a thin sample. 215 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 Frontier on SJU to EWR

Put together: treat all of this as provisional. 215 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 69.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 209 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