Route reliability record
SJU→ORD
San Juan to Chicago
- Flights
- 1,397
- Period
- July 2025 to June 2026
- Distance
- 2,072 mi
- Carriers
- 4
This route lands a B, 2 points 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 a little over an hour on average. That is a workable record, not a spotless one. That rests on 1,397 SJU to ORD flights, of which United Airlines flew 665 at 82.1% on time.
Best time to fly SJU to ORD: a 8am–11am departure, ideally on a Saturday. Flights in that window arrived on time 94.9% of the time and Saturday flights 82.5%, against 79.5% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
79.5%
Arrivals under 15 minutes late, of 1,348 completed flights
Avg delay
69 min
Across delayed arrivals only, not all flights
Cancelled
2.15%
National rate is 1.81%
Best carrier
United
82.1% on time across 665 flights
These figures cover 1,397 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
Which airline is most reliable on SJU to ORD
The choice of carrier is not cosmetic here. United Airlines arrives on time 82.1% of the time; American Airlines manages 74.5%. Sample sizes sit next to every figure, because a two-point gap across 426 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 12 | 90.9% | 16 min | 0.00% | A+ |
| United Airlines | 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 |
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 SJU to ORD
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.
Best ways to make this trip
The most reliable ways to fly San Juan to Chicago
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. SJU → ORDSan Juan to Chicago | United Airlines | 81.6% | 82.1% | 0.60% | 5am–8am, Sat | UA 2089 07:40 |
| 2. SJU → ORDSan Juan to Chicago | American Airlines | 73.1% | 74.5% | 1.88% | 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 26 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am306 flights92.6%
- 8am–11am138 flights94.9%
- 11am–2pm108 flights75.7%
- 2pm–5pm560 flights69.3%
- 5pm–8pm185 flights78.6%
- 8pm–5am100 flights81.4%
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 94.9% of the time, against 69.3% 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 560 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 18 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 October, when the on-time rate falls to 68.5%. June is the strongest month at 86.5%. Moving a flexible trip across that boundary buys 18 points. March was the busiest month here, with 177 flights.
Across the week, Saturday is the strongest day at 82.5% on time and Monday the weakest at 75.0%. 8 points is a smaller lever than departure hour, but it is free.
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 19,000 reported delay minutes.
- 35%Late-arriving aircraft
- 34%Carrier
- 24%National Airspace System
- 8%Extreme weather
- 0%Security
35% 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 19,000 reported delay minutes here, that single category outweighs weather by 4 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 19,119 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 94.9% on time here.
Cancellations sit at 2.15% against a national 1.81%, which is ordinary. Diversions add another 1.36%.
Connections and stage length
What a delay here actually costs
5.9% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
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 73.8% on time across 1,403 flights, 6 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 6 points of difference.
The sample behind these figures is 1,397 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 ORD 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. June runs 86.5% on time and October 68.5%, a swing of 18 points. If the dates move at all, move them out of October before you think about anything else. 1,348 completed flights over 12 months sit behind that.
Common questions
SJU to ORD questions
How often is SJU to ORD delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.5% of the 1,397 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on SJU to ORD?
United Airlines leads at 82.1% on time across 665 flights. American Airlines is at the other end on 74.5%, 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 SJU to ORD?
The 8am–11am departure window is the strongest at 94.9% on time. The 2pm–5pm window is the weakest at 69.3%, 26 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 October delays on SJU to ORD?
October is the weakest month at 68.5% on time, compared with 86.5% in June. Across the year that is 18 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
- ORD to SJU — the return legseparate record
- Luis Munoz Marin International (SJU) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- United Airlines on SJU to ORD82.1%
- Spirit Airlines on SJU to ORD80.3%
- American Airlines on SJU to ORD74.5%
- SJU to MCO, a related route78.9%
- LGA to ORD, a related route67.3%
- SJU to JFK, a related route79.3%
- Frontier Airlines on-time record90.9%
- United Airlines on-time record82.1%
- Spirit Airlines on-time record80.3%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. SJU to ORD and ORD to SJU are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.