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DelayAtlas

Route reliability record

PHLSJU

Philadelphia to San Juan

Flights
1,879
Period
July 2025 to June 2026
Distance
1,576 mi
Carriers
4
D−GRADE

This route draws a D−. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is an hour and a half behind schedule. Build slack into anything you connect to. That rests on 1,879 PHL to SJU flights, of which American Airlines flew 701 at 68.2% on time.

Best time to fly PHL to SJU: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 74.7% of the time and Tuesday flights 70.5%, against 63.1% for the route overall.

The national on-time rate over the same period is 77.6%, so this route runs 14 points behind the country as a whole. Across a thousand flights that is about 145 extra late arrivals.

Key figures

On time

63.1%

Arrivals under 15 minutes late, of 1,812 completed flights

Avg delay

83 min

Across delayed arrivals only, not all flights

Cancelled

3.19%

National rate is 1.81%

Best carrier

American

68.2% on time across 701 flights

These figures cover 1,879 flights between July 2025 and June 2026. Beyond the headline rate, 14.9% 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 PHL to SJU

The choice of carrier is not cosmetic here. American Airlines arrives on time 68.2% of the time; Frontier Airlines manages 57.9%. Sample sizes sit next to every figure, because a two-point gap across 865 flights means less than a ten-point one.

On-time performance by carrier on PHL to SJU
AirlineFlightsOn timeAvg delayCancelledGrade
JetBlue Airwaysthin sample9778.1%138 min0.00%B+
American Airlines70168.2%98 min2.00%C
Spirit Airlinesthin sample21659.8%69 min7.87%D−
Frontier Airlines86557.9%75 min3.35%D−

Frontier Airlines cancels 3.4% 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

Flights on PHL to SJU

The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.

Best ways to make this trip

The most reliable ways to fly Philadelphia to San Juan

Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.

Most reliable ways to fly from PHL to SJU
OptionAirlineSuccessOn timeCancelledBest departureMost punctual flight
1. PHLSJUPhiladelphia to San JuanAmerican Airlines66.8%68.2%2.00%8am–11am, Tue
2. PHLSJUPhiladelphia to San JuanFrontier Airlines56.0%57.9%3.35%11am–2pm, TueF9 1016 06:00

Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.

Plan this trip by month, day and time

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 28 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am202 flights64.1%
  • 8am–11am345 flights74.7%
  • 11am–2pm377 flights72.0%
  • 2pm–5pm114 flights46.4%
  • 5pm–8pm366 flights55.1%
  • 8pm–5am475 flights56.9%

Scale runs 40% to 80%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 74.7% of the time, against 46.4% for the afternoon window. That is 28 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 475 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 34 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.

On-time rate by calendar month56J60F59M74A78M72J44J53A60S62O72N54D
Darker means more delays. Figures are on-time percentages.May best, July worst

July is the worst month at 43.7% on time, 34 points below May, the best at 77.6%. 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. April was the busiest month here, with 224 flights.

Across the week, Tuesday is the strongest day at 70.5% on time and Sunday the weakest at 57.8%. 13 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week59.8Mon70.5Tue68.7Wed62.5Thu64.2Fri59.8Sat57.8Sun
Monday: 59.8 percent on time. Tuesday: 70.5 percent on time. Wednesday: 68.7 percent on time. Thursday: 62.5 percent on time. Friday: 64.2 percent on time. Saturday: 59.8 percent on time. Sunday: 57.8 percent on time

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 56,000 reported delay minutes.

  • Carrier
    41%
  • Late-arriving aircraft
    31%
  • National Airspace System
    24%
  • Extreme weather
    5%
  • Security
    0%

The largest share of delay minutes, 41%, 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 23,000 of the 56,000 delay minutes reported here. The split is drawn from 55,759 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 74.7% on time here.

Cancellations run at 3.19%, 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. 14.9% 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 1,576 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 70.5% on time across 1,881 flights, 7 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 7 points of difference.

The sample behind these figures is 1,879 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.

Work out the risk of missing a connection in SJU after this flight

What to do with this

Booking this route

Put together: the delay figures matter less here than the 3.19% 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. 1,812 completed flights over 12 months sit behind that.

Common questions

PHL to SJU questions

How often is PHL to SJU delayed?

Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 36.9% of the 1,879 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 PHL to SJU?

American Airlines leads at 68.2% on time across 701 flights. Frontier Airlines is at the other end on 57.9%, a gap of 10 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 PHL to SJU?

The 8am–11am departure window is the strongest at 74.7% on time. The 2pm–5pm window is the weakest at 46.4%, 28 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 PHL to SJU?

July is the weakest month at 43.7% on time, compared with 77.6% in May. Across the year that is 34 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

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

Embed PHL to SJU’s on-time badge on your site

Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.

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.