Carrier route record

UASJU→ORD

United Airlines · San Juan to Chicago

Flights: 665
Period: July 2025 to June 2026
Share of route: 48%
Carriers: 4

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

United on SJU to ORD lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by roughly 40 minutes on average. That is a workable record, not a spotless one. That rests on 665 flights, with a median arrival 9 minutes early.

Set against the rest of the country, United's SJU to ORD record is 5 points better than the US average of 77.6%. That gap is worth roughly 45 fewer late arrivals for every thousand flights.

On time

82.1%

Arrivals under 15 minutes late, of 655 completed flights

Avg delay

39 min

Across delayed arrivals only, not all flights

Cancelled

0.60%

National rate is 1.81%

Whole route

79.5%

Every carrier on SJU to ORD, 1,397 flights

These figures cover 665 flights between July 2025 and June 2026. The median arrival is 9 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

Carrier by carrier

United against every carrier on SJU to ORD

United flew 665 of the 1,397 flights on SJU to ORD, about 48% of it. Its 82.1% on time is 3 points better than the route as a whole, which runs 79.5%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Frontier at 90.9% to American at 74.5%. 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 SJU to ORD
Airline	Flights	On time	Avg delay	Cancelled	Grade
Frontier Airlinesthin sample	12	90.9%	16 min	0.00%	A+
United Airlines (this page)	665	82.1%	39 min	0.60%	B+
Spirit Airlinesthin sample	294	80.3%	80 min	6.12%	B−
American Airlines	426	74.5%	99 min	1.88%	C

Flight by flight

United flight numbers on SJU to ORD

Departure window

When United runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 26 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–8am171 flights96.4%
8am–11am125 flights94.3%
11am–2pm—
2pm–5pm243 flights70.3%
5pm–8pm126 flights73.4%
8pm–5am—

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 96.4% of the time, against 70.3% for the afternoon window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 243 flights scheduled in it.

Across the year

United on SJU to ORD through the year

Darker means more delays. Figures are on-time percentages.April best, October worst

April is the best month on the calendar at 93.1% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. March was the busiest month here, with 66 flights.

Across the week, Saturday is the strongest day at 86.5% on time and Monday the weakest at 76.6%. 10 points is a smaller lever than departure hour, but it is free.

Delay causes

Why United runs late on this route

One category carries most of the weight here. National Airspace System accounts for 49% of the 4,538 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.

National Airspace System
49%
Late-arriving aircraft
36%
Carrier
15%
Extreme weather
0%

36% 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 4,538 reported delay minutes here, that single category outweighs weather by 36 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 4,538 reported delay minutes.

49% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 2,222 minutes out of 4,538, against a national NAS share of 21%.

Cancellations are rare at 0.60%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 2.9% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

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 is a different operation and performs like one: it runs 78.9% on time across 665 flights, 3 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 3 points of difference.

One caution: this is a thin sample. 665 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 United on SJU to ORD

Put together: treat all of this as provisional. 665 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 82.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 655 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