Carrier route record
UAORD→SJU
United Airlines · Chicago to San Juan
- Flights
- 665
- Period
- July 2025 to June 2026
- Share of route
- 47%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on ORD to SJU lands a B+, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 45 minutes on average. That is a workable record, not a spotless one. That rests on 665 flights, with a median arrival 4 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate United on ORD to SJU from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.9%
Arrivals under 15 minutes late, of 663 completed flights
Avg delay
45 min
Across delayed arrivals only, not all flights
Cancelled
0.30%
National rate is 1.81%
Whole route
73.8%
Every carrier on ORD to SJU, 1,403 flights
These figures cover 665 flights between July 2025 and June 2026. The median arrival is 4 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 ORD to SJU
United flew 665 of the 1,403 flights on ORD to SJU, about 47% of it. Its 78.9% on time is 5 points better than the route as a whole, which runs 73.8%. Ranked by on-time rate it is first 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 665 | 78.9% | 45 min | 0.30% | B+ |
| Frontier Airlinesthin sample | 12 | 75.0% | 20 min | 0.00% | B+ |
| American Airlines | 429 | 72.9% | 64 min | 1.40% | C |
| Spirit Airlinesthin sample | 297 | 62.7% | 74 min | 6.73% | D− |
Flight by flight
United flight numbers on ORD to SJU
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 24 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–8am4 flights—
- 8am–11am365 flights80.8%
- 11am–2pm—
- 2pm–5pm247 flights80.5%
- 5pm–8pm49 flights57.1%
- 8pm–5am—
Scale runs 50% to 85%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 57.1% on time, against 80.8% for the 8am–11am 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 365 flights scheduled in it.
Across the year
United on ORD to SJU through the year
Delays peak in March, when the on-time rate falls to 62.1%. February is the strongest month at 98.2%. Moving a flexible trip across that boundary buys 36 points. March was the busiest month here, with 66 flights.
Across the week, Wednesday is the strongest day at 84.0% on time and Monday the weakest at 73.7%. 10 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United 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 6,333 reported delay minutes.
- 37%National Airspace System
- 30%Carrier
- 22%Late-arriving aircraft
- 11%Extreme weather
37% 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 2,326 minutes out of 6,333, against a national NAS share of 21%. The split is drawn from 6,333 reported delay minutes.
Cancellations are rare at 0.30%, 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 4.2% 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 82.1% on time across 665 flights, 3 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 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 ORD to SJU
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 78.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 663 completed flights over 12 months sit behind that.
Related
Where to go next
- ORD to SJU, every carrier
- United on SJU to ORD, the return leg
- American Airlines on ORD to SJU72.9%
- Spirit Airlines on ORD to SJU62.7%
- United Airlines network-wide record
- Chicago O'Hare International (ORD) delay statistics
- Luis Munoz Marin International (SJU) delay statistics
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
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.