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DelayAtlas

Carrier performance at one airport

B6SJU

JetBlue Airways at Luis Munoz Marin International

Departures
11,597
Period
June 2025 to May 2026
Routes
17
Rank here
#5 of 7
BGRADE

JetBlue Airways at San Juan sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.4%. The late ones land a little over an hour behind schedule. That rests on 11,597 flights, of which Delta Air Lines flew 3,644 at 87.7% on time.

Measured against the airport rather than the country, JetBlue Airways runs 3 points behind the 77.7% weighted average across all carriers at SJU. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.

Key figures

On time

75.2%

11,338 completed departures

Avg delay

75 min

Across delayed flights only

Cancelled

1.87%

At SJU, this carrier only

Rank here

#5

Of 7 carriers clearing the floor at SJU

These figures cover 12,000 flights between June 2025 and May 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.

Against the competition

Every carrier at SJU, ranked

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 87.7% of the time; Frontier Airlines manages 70.1%. Sample sizes sit next to every figure, because a two-point gap across 4,873 flights means less than a ten-point one.

On-time performance of all carriers departing SJU
AirlineFlightsOn timeAvg delayCancelledGrade
Delta Air Lines3,64487.7%73 min1.56%A
United Airlines3,57183.5%68 min1.37%B
Southwest Airlines3,92480.9%47 min0.71%B+
American Airlines4,84479.8%103 min1.47%B
JetBlue Airways (this page)11,59775.2%75 min1.87%B
Spirit Airlines3,03073.3%75 min3.80%C−
Frontier Airlines4,87370.1%89 min2.50%C

Spirit Airlines cancels 3.8% 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.

Route by route

Where JetBlue Airways flies from SJU

JetBlue Airways operates 17 routes out of SJU with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.

JetBlue Airways routes from SJU
RouteFlightsOn timeAvg delayCancelledGrade
SJU to JFK · New York2,23875.1%78 min3.08%B−
SJU to MCO · Orlando2,09577.3%73 min0.95%B+
SJU to FLL · Fort Lauderdale1,60977.0%73 min1.24%B
SJU to BOS · Boston1,43770.5%74 min2.92%C
SJU to BDL · Hartford72670.1%77 min1.93%C
SJU to EWR · Newark61575.8%82 min2.93%B
SJU to TPA · Tampa59476.3%65 min0.51%B+
SJU to DCA · Washington36570.5%86 min1.37%C
SJU to HPN · White Plainsthin sample36372.6%100 min2.48%C
SJU to STT · Charlotte Amaliethin sample35172.4%64 min0.57%C+
SJU to PVD · Providencethin sample33469.7%69 min1.80%C
SJU to RDU · Raleighthin sample32985.8%76 min1.52%A
SJU to STX · Christianstedthin sample31276.7%52 min0.96%B+
SJU to PHL · Philadelphiathin sample6793.9%25 min0.00%A+
SJU to JAX · Jacksonvillethin sample5783.9%48 min1.75%B
SJU to BUF · Buffalothin sample3889.5%66 min0.00%A+
SJU to ORF · Norfolkthin sample3894.7%54 min0.00%A+

Departure window

Best time of day for this operation

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 18 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am2,269 flights87.1%
  • 8am–11am1,201 flights83.3%
  • 11am–2pm1,861 flights76.5%
  • 2pm–5pm2,321 flights68.5%
  • 5pm–8pm2,360 flights68.7%
  • 8pm–5am1,585 flights69.5%

Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 87.1% of the time, against 68.5% for the afternoon window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on.

Across the year

Seasonal pattern

On-time rate by calendar month69J68F75M78A86M84J71J67A76S76O78N73D
Darker means more delays. Figures are on-time percentages.May best, August worst

August is the worst month at 66.9% on time, 19 points below May, the best at 85.5%. 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.

Delay causes

What holds this operation up

  • Late-arriving aircraft
    50%
  • Carrier
    37%
  • National Airspace System
    12%
  • Extreme weather
    1%
  • Security
    0%

50% 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 211,000 reported delay minutes here, that single category outweighs weather by 50 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.

Cancellations sit at 1.87% against a national 1.80%, which is ordinary. Diversions add another 0.36%.

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 8.2% 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.

The sample behind these figures is 11,597 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.

Put together: the calendar is the biggest lever here, not the carrier or the hour. May runs 85.5% on time and August 66.9%, a swing of 19 points. If the dates move at all, move them out of August before you think about anything else.

Common questions

JetBlue Airways at SJU

How often is JetBlue Airways at SJU 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 24.8% of the 11,597 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 JetBlue Airways at SJU?

Delta Air Lines leads at 87.7% on time across 3,644 flights. Frontier Airlines is at the other end on 70.1%, a gap of 18 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 JetBlue Airways at SJU?

The 5am–8am departure window is the strongest at 87.1% on time. The 2pm–5pm window is the weakest at 68.5%, 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 August delays on JetBlue Airways at SJU?

August is the weakest month at 66.9% on time, compared with 85.5% in May. Across the year that is 19 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

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