Carrier route record
UASJU→ORD
United Airlines · San Juan to Chicago
- Flights
- 657
- Period
- September 2025 to August 2026
- Share of route
- 48%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on SJU to ORD lands a B+, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 45 minutes on average. That rests on 657 flights, with a median arrival 9 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate United on SJU to ORD from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.5%
Arrivals under 15 minutes late, of 646 completed flights
Avg delay
43 min
Across delayed arrivals only, not all flights
Cancelled
0.61%
National rate is 1.89%
Whole route
78.3%
Every carrier on SJU to ORD, 1,383 flights
These figures cover 657 flights between September 2025 and August 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.
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Carrier by carrier
United against every carrier on SJU to ORD
United flew 657 of the 1,383 flights on SJU to ORD, about 48% of it. Its 80.5% on time is 2 points better than the route as a whole, which runs 78.3%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from United at 80.5% to Frontier at 65.2%. 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 657 | 80.5% | 43 min | 0.61% | B+ |
| Spirit Airlinesthin sample | 227 | 77.8% | 82 min | 7.93% | B− |
| American Airlines | 426 | 77.3% | 101 min | 2.11% | B |
| Frontier Airlinesthin sample | 73 | 65.2% | 115 min | 2.74% | C |
Flight by flight
United flight numbers on SJU to ORD
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
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 32 points, against half a point between the best and worst carrier.
- 5am–8am163 flights97.5%
- 8am–11am125 flights94.3%
- 11am–2pm—
- 2pm–5pm243 flights65.7%
- 5pm–8pm126 flights73.4%
- 8pm–5am—
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 97.5% of the time, against 65.7% for the afternoon window. That is 32 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
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, Thursday is the strongest day at 85.6% on time and Monday the weakest at 74.2%, a spread of 11 points.
Arrival by arrival
How late United on SJU to ORD runs when it is late
United on SJU to ORD often beats the schedule: 245 of 646 completed flights, 38%, arrived 15 minutes or more early. Most of the lateness is short. 63 of the 126 late arrivals were under half an hour behind, and 23 reached an hour or more.
- 15+ min early245 flights37.9%
- Within 15 min275 flights42.6%
- 15–29 min late63 flights9.8%
- 30–59 min late40 flights6.2%
- 1–2 hours late17 flights2.6%
- 2+ hours late6 flights0.9%
Scale runs 0% to 100%.
Share of 646 completed flights by arrival against schedule.
15 of 69 late departures made up the time and arrived on time, 22% of them. In the other direction, 72 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at ORD.
The worst days
Worst days for United on SJU to ORD
The latest arrival of the period was on 12 August 2026, 5 hours 57 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 12 August 2026 | 5 hours 57 minutes | Late-arriving aircraft |
| 15 August 2026 | 2 hours 58 minutes | Late-arriving aircraft |
| 27 May 2026 | 2 hours 30 minutes | Carrier |
| 7 September 2025 | 2 hours 28 minutes | Late-arriving aircraft |
| 8 November 2025 | 2 hours 9 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
Late-arriving aircraft accounts for 48% of the 5,385 delay minutes carriers reported here, and the remaining four split what is left.
- 48%Late-arriving aircraft
- 42%National Airspace System
- 10%Carrier
- 0%Extreme weather
48% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,385 reported delay minutes here, that single category outweighs weather by 48 to one. The split is drawn from 5,385 reported delay minutes.
42% 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 2,243 minutes out of 5,385, against a national NAS share of 21%.
Cancellations are rare at 0.61%, below the national 1.89% 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 3.6% land an hour or more behind schedule, against 8.3% 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 runs 79.2% on time across 657 flights, within about a point 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. 657 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. 657 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 80.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 646 completed flights over 12 months sit behind that.
Related
Where to go next
- SJU to ORD, every carrier
- United on ORD to SJU, the return leg
- Spirit Airlines on SJU to ORD77.8%
- American Airlines on SJU to ORD77.3%
- United Airlines network-wide record
- Luis Munoz Marin International (SJU) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.