San Juan, PR · departure reliability
SJU
Luis Munoz Marin International
- Departures
- 35,332
- Period
- September 2025 to August 2026
- Carriers
- 7
- US rank
- #47 by volume
San Juan
Luis Munoz Marin International lands a B, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 35,332 flights, of which Delta Air Lines flew 3,626 at 87.5% on time.
Delta Air Lines is the most reliable of the seven carriers covered here at 87.5% on time across 3,626 flights.
Key figures
On time
77.7%
Departures arriving under 15 minutes late at their destination
Avg delay
78 min
Across delayed flights only
Cancelled
2.11%
National rate is 1.89%
Best carrier
Delta
87.5% on time here
These figures cover 35,000 flights between September 2025 and August 2026. The median arrival is 6 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 airlines run best out of SJU
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 87.5% of the time; Spirit Airlines manages 69.5%. Sample sizes sit next to every figure, because a two-point gap across 2,066 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| JetBlue Airways | 12,134 | 73.9% | 77 min | 2.60% | C |
| American Airlines | 5,024 | 81.4% | 95 min | 1.43% | B |
| Frontier Airlines | 4,998 | 73.4% | 90 min | 2.34% | C |
| Southwest Airlines | 3,888 | 79.0% | 46 min | 0.80% | B+ |
| Delta Air Lines | 3,626 | 87.5% | 70 min | 1.63% | A |
| United Airlines | 3,596 | 84.5% | 73 min | 1.22% | B |
| Spirit Airlines | 2,066 | 69.5% | 78 min | 5.23% | C− |
Spirit Airlines cancels 5.2% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Busiest routes out of SJU
Route-level records vary far more than the airport average. These are the 17 busiest departures from SJU, each with its own on-time rate against the airport-wide 77.7%.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SJU to MCO · Orlando | 6,134 | 78.0% | 77 min | 1.21% | B |
| SJU to JFK · New York | 3,560 | 77.8% | 82 min | 3.93% | B− |
| SJU to MIA · Miami | 2,650 | 78.9% | 89 min | 0.94% | B+ |
| SJU to FLL · Fort Lauderdale | 2,356 | 76.2% | 73 min | 1.44% | B |
| SJU to ATL · Atlanta | 2,097 | 81.6% | 80 min | 1.34% | B |
| SJU to EWR · Newark | 2,077 | 74.6% | 88 min | 3.27% | C− |
| SJU to PHL · Philadelphia | 1,992 | 71.9% | 85 min | 3.61% | C− |
| SJU to BOS · Boston | 1,916 | 70.8% | 74 min | 3.18% | C− |
| SJU to TPA · Tampa | 1,562 | 77.2% | 71 min | 1.92% | B |
| SJU to ORD · Chicago | 1,383 | 78.3% | 74 min | 2.39% | B |
| SJU to BWI · Baltimore | 1,153 | 78.9% | 59 min | 2.43% | B |
| SJU to CLT · Charlotte | 1,086 | 86.0% | 107 min | 1.57% | A |
| SJU to DFW · Dallas-Fort Worth | 975 | 80.3% | 77 min | 2.87% | B |
| SJU to BDL · Hartford | 968 | 69.8% | 69 min | 2.27% | C |
| SJU to IAH · Houston | 909 | 88.7% | 55 min | 0.55% | A+ |
| SJU to IAD · Washington | 698 | 88.7% | 70 min | 0.72% | A+ |
| SJU to RDU · Raleigh | 467 | 82.1% | 74 min | 1.50% | B |
Departure window
The best time of day to leave SJU
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 18 points between the best and worst carrier.
- 5am–8am8,050 flights89.2%
- 8am–11am2,934 flights86.5%
- 11am–2pm5,249 flights77.7%
- 2pm–5pm8,437 flights72.0%
- 5pm–8pm6,500 flights71.7%
- 8pm–5am4,162 flights70.0%
Scale runs 60% to 95%.
Book the early departure. Flights leaving between 5am–8am arrive on time 89.2% of the time, against 70.0% for the overnight window. That is 19 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 8,437 flights scheduled in it.
Explore
Filter SJU departures 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 departures from San Juan (SJU), the best departure window is 5am–8am at 89.2% on time and the worst is 8pm–5am at 70.0%, a wide gap of 19.2 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am89.2%
- 8–11am86.5%
- 11am–2pm77.7%
- 2–5pm72.0%
- 5–8pm71.7%
- 8pm–5am70.0%
best all US flightsScale 60% to 95%.
Across the year
When SJU runs late
SJU's year swings by 13 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.
July is the worst month at 71.5% on time, 13 points below May, the best at 84.7%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. March was the busiest month here, with 3,441 flights.
Across the week, Wednesday is the strongest day at 80.8% on time and Sunday the weakest at 73.8%, a spread of 7 points.
SJU month by month
From Europe
Transatlantic routes into SJU
1 European airport sends scheduled passenger flights to SJU, 1,067 flights a year in both directions by the DOT's international count. The DOT keeps no delay record for international flights; the UK routes carry the CAA's departure punctuality, and every route sets its departure airport's EUROCONTROL figures beside SJU's own record above.
Delay causes
Why SJU gets delayed
Late-arriving aircraft accounts for 52% of the 596,000 delay minutes carriers reported here, and the remaining four split what is left.
- 52%Late-arriving aircraft
- 35%Carrier
- 12%National Airspace System
- 1%Extreme weather
- 0%Security
52% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 596,000 reported delay minutes here, that single category outweighs weather by 44 to one. The split is drawn from 595,762 reported delay minutes.
The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 207,000 of the 596,000 delay minutes reported here.
Cancellations sit at 2.11% against a national 1.89%, which is ordinary. Diversions add another 0.40%.
7.9% of arrivals land an hour or more late, close to the national 8.3%, so 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.
35,332 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.
What to do with this
Flying out of SJU
Put together: the calendar is the biggest lever here, not the carrier or the hour. May runs 84.7% on time and July 71.5%, a swing of 13 points. If the dates move at all, move them out of July before you think about anything else. 34,443 completed flights over 12 months sit behind that.
Common questions
SJU delay questions
How often is San Juan (SJU) delayed?
Roughly 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 22.3% of the 35,332 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 San Juan (SJU)?
Delta Air Lines leads at 87.5% on time across 3,626 flights. Spirit Airlines is at the other end on 69.5%, a gap of 18 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 San Juan (SJU)?
The 5am–8am departure window is the strongest at 89.2% on time. The 8pm–5am window is the weakest at 70.0%, 19 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 July delays on San Juan (SJU)?
July is the weakest month at 71.5% on time, compared with 84.7% in May. Across the year that is 13 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 MCO — Orlando78.0%
- SJU to JFK — New York77.8%
- SJU to MIA — Miami78.9%
- SJU to FLL — Fort Lauderdale76.2%
- SJU to ATL — Atlanta81.6%
- SJU to EWR — Newark74.6%
- JetBlue Airways on-time record73.9%
- American Airlines on-time record81.4%
- Frontier Airlines on-time record73.4%
- Southwest Airlines on-time record79.0%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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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.