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DelayAtlas

Carrier route record

AAORDSJU

American Airlines · Chicago to San Juan

Flights
429
Period
July 2025 to June 2026
Share of route
31%
Carriers
4
CGRADE

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

American on ORD to SJU sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 429 flights, with a median arrival 4 minutes early.

The national on-time rate over the same period is 77.6%, so American on ORD to SJU runs 5 points behind the country as a whole. Across a thousand flights that is about 47 extra late arrivals.

Key figures

On time

72.9%

Arrivals under 15 minutes late, of 421 completed flights

Avg delay

64 min

Across delayed arrivals only, not all flights

Cancelled

1.40%

National rate is 1.81%

Whole route

73.8%

Every carrier on ORD to SJU, 1,403 flights

These figures cover 429 flights between July 2025 and June 2026. Beyond the headline rate, 11.6% 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

American against every carrier on ORD to SJU

American flew 429 of the 1,403 flights on ORD to SJU, about 31% of it. Its 72.9% on time is about level with the route as a whole at 73.8%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from United at 78.9% to Spirit at 62.7%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on ORD to SJU
AirlineFlightsOn timeAvg delayCancelledGrade
United Airlines66578.9%45 min0.30%B+
Frontier Airlinesthin sample1275.0%20 min0.00%B+
American Airlines (this page)42972.9%64 min1.40%C
Spirit Airlinesthin sample29762.7%74 min6.73%D−

Departure window

When American runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 28 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am
  • 8am–11am287 flights74.9%
  • 11am–2pm
  • 2pm–5pm37 flights71.4%
  • 5pm–8pm41 flights51.2%
  • 8pm–5am64 flights79.0%

Scale runs 45% to 85%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 51.2% on time, against 79.0% for the 8pm–5am 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 287 flights scheduled in it.

Across the year

American on ORD to SJU through the year

On-time rate by calendar month71J80F69M83A80M37J74J74ASON74D
Darker means more delays. Figures are on-time percentages.April best, June worst

June is the worst month at 36.7% on time, 47 points below April, the best at 83.3%. 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 62 flights.

Across the week, Wednesday is the strongest day at 76.4% on time and Sunday the weakest at 68.3%. 8 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week69.4Mon75.0Tue76.4Wed75.8Thu71.0Fri75.4Sat68.3Sun
Monday: 69.4 percent on time. Tuesday: 75.0 percent on time. Wednesday: 76.4 percent on time. Thursday: 75.8 percent on time. Friday: 71.0 percent on time. Saturday: 75.4 percent on time. Sunday: 68.3 percent on time

Delay causes

Why American 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 7,255 reported delay minutes.

  • Carrier
    37%
  • Late-arriving aircraft
    26%
  • National Airspace System
    25%
  • Extreme weather
    12%

Extreme weather accounts for 12% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 1.9 times the usual weather exposure. The split is drawn from 7,255 reported delay minutes.

The largest share of delay minutes, 37%, 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 2,691 of the 7,255 delay minutes reported here.

Cancellations sit at 1.40% against a national 1.81%, which is ordinary. Diversions add another 0.47%.

Connections and stage length

What a delay here costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.6% 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 2,072 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 runs 74.5% on time across 426 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 429 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 American on ORD to SJU

Put together: treat all of this as provisional. 429 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 72.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 421 completed flights over 12 months sit behind that.

Related

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.