Route reliability record
ORD→SJU
Chicago to San Juan
- Flights
- 1,390
- Period
- September 2025 to August 2026
- Distance
- 2,072 mi
- Carriers
- 4
This route sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 1,390 ORD to SJU flights, of which United Airlines flew 657 at 79.2% on time.
Best time to fly ORD to SJU: a 2pm–5pm departure, ideally on a Wednesday. Flights in that window arrived on time 78.8% of the time and Wednesday flights 78.4%, against 73.2% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 4 points behind the country as a whole. Across a thousand flights that is about 41 extra late arrivals.
Key figures
On time
73.2%
Arrivals under 15 minutes late, of 1,356 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
2.23%
National rate is 1.89%
Best carrier
United
79.2% on time across 657 flights
These figures cover 1,390 flights between September 2025 and August 2026. Beyond the headline rate, 9.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
Which airline is most reliable on ORD to SJU
The choice of carrier is not cosmetic here. United Airlines arrives on time 79.2% of the time; American Airlines manages 71.2%. Sample sizes sit next to every figure, because a two-point gap across 429 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 657 | 79.2% | 52 min | 0.30% | B+ |
| American Airlines | 429 | 71.2% | 64 min | 1.63% | C |
| Frontier Airlinesthin sample | 72 | 66.7% | 189 min | 4.17% | C− |
| Spirit Airlinesthin sample | 232 | 60.8% | 76 min | 8.19% | D− |
United leads American by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on ORD to SJU
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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.
Best ways to make this trip
The most reliable ways to fly Chicago to San Juan
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. ORD → SJUChicago to San Juan | United Airlines | 79.0% | 79.2% | 0.30% | 2pm–5pm, Wed | UA 695 14:20 |
| 2. ORD → SJUChicago to San Juan | American Airlines | 70.0% | 71.2% | 1.63% | 8pm–5am, Wed | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 21 points, against 8 points between the best and worst carrier.
- 5am–8am41 flights70.3%
- 8am–11am626 flights77.9%
- 11am–2pm116 flights59.5%
- 2pm–5pm328 flights78.8%
- 5pm–8pm103 flights57.8%
- 8pm–5am176 flights64.0%
Scale runs 50% to 85%.
The 5pm–8pm window is where this operation falls apart: 57.8% on time, against 78.8% for the 2pm–5pm 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 626 flights scheduled in it.
Explore
Filter ORD to SJU by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On ORD to SJU, the best departure window is 2pm–5pm at 78.8% on time and the worst is 5pm–8pm at 57.8%, a wide gap of 21.0 points. All US flights leaving 2pm–5pm ran 71.9%.
- 5–8am70.3%
- 8–11am77.9%
- 11am–2pm59.5%
- 2–5pm78.8%
- 5–8pm57.8%
- 8pm–5am64.0%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 28 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
Delays peak in March, when the on-time rate falls to 59.4%. February is the strongest month at 87.1%. Moving a flexible trip across that boundary buys 28 points. March was the busiest month here, with 179 flights.
Across the week, Wednesday is the strongest day at 78.4% on time and Monday the weakest at 67.5%, a spread of 11 points.
Delay causes
Why this route gets delayed
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 25,000 reported delay minutes.
- 36%Carrier
- 31%Late-arriving aircraft
- 25%National Airspace System
- 9%Extreme weather
- 0%Security
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 9,134 of the 25,000 delay minutes reported here. The split is drawn from 25,444 reported delay minutes.
Cancellations sit at 2.23% against a national 1.89%, which is ordinary. Diversions add another 0.22%.
Connections and stage length
What a delay here actually costs
9.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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 is a different operation and performs like one: it runs 78.3% on time across 1,383 flights, 5 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 5 points of difference.
The sample behind these figures is 1,390 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.
Work out the risk of missing a connection in SJU after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 87.1% on time and March 59.4%, a swing of 28 points. If the dates move at all, move them out of March before you think about anything else. 1,356 completed flights over 12 months sit behind that.
Common questions
ORD to SJU questions
How often is ORD to SJU delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 26.8% of the 1,390 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on ORD to SJU?
United Airlines leads at 79.2% on time across 657 flights. American Airlines is at the other end on 71.2%, a gap of 8 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 ORD to SJU?
The 2pm–5pm departure window is the strongest at 78.8% on time. The 5pm–8pm window is the weakest at 57.8%, 21 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 March delays on ORD to SJU?
March is the weakest month at 59.4% on time, compared with 87.1% in February. Across the year that is 28 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
- SJU to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- Luis Munoz Marin International (SJU) delay statistics
- United Airlines on ORD to SJU79.2%
- American Airlines on ORD to SJU71.2%
- Spirit Airlines on ORD to SJU60.8%
- ORD to LGA, a related route66.6%
- MCO to SJU, a related route73.8%
- ORD to BOS, a related route66.6%
- United Airlines on-time record79.2%
- American Airlines on-time record71.2%
- Frontier Airlines on-time record66.7%
- The best time of day to fly, according to 7.05 million flight records
- How often a connection fails at the major US hubs
Direction matters. ORD to SJU and SJU to ORD are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed ORD to SJU’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
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.