San Juan (SJU) to Detroit (DTW): On-Time Performance
Data through July 2026
San Juan (SJU) to Detroit (DTW) is a thinner route than most in this dataset — 357 departures over the past year, roughly 7 a week — so treat these numbers as indicative rather than definitive. Of the flights that did operate, 82% arrived on time.
- On-time
- 82%
- arrived <15 min late
- Avg delay
- 13 min
- completed flights
- Cancelled
- 1.0%
- Flights/day
- 0.98
- last 12 months
- Duration
- 4h 46m
- scheduled
- Distance
- 1,930 mi
Best airline from SJU to DTW
2 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| Delta Air Linesmost reliable | 83% | 14 min | 1.0% | 692 |
| Spirit Airlines | 80% | 10 min | 1.4% | 72 |
Monthly on-time trend
Best time to fly from SJU to DTW
Aim for departures around 1 p.m. (93% on-time); avoid 4 p.m. departures (52%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 85% | 7 min |
| Tuesday | 84% | 8 min |
| Wednesdaybest | 87% | 8 min |
| Thursday | 79% | 23 min |
| Friday | 79% | 16 min |
| Saturday | 83% | 16 min |
| Sunday | 79% | 12 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft52%
- Airline operations27%
- National airspace system20%
- Weather1%
Frequently asked questions
- How often are flights from SJU to DTW delayed?
- 18% of SJU–DTW flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 13 minutes.
- Which airline is most reliable from SJU to DTW?
- Delta Air Lines has the best on-time record on this route at 83%, based on 692 flights. 2 airlines flew SJU–DTW frequently enough to compare in this period.
- What is the best time of day to fly from SJU to DTW?
- Departures around 1 p.m. have the best record (93% on-time), while departures around 4 p.m. have the worst (52%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SJU to DTW?
- The scheduled SJU–DTW flight time averages 4h 46m over 1,930 miles. Actual arrival times vary — flights on this route land 15+ minutes late 18% of the time.
- How often are SJU to DTW flights cancelled?
- 1% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from SJU to DTW?
- January 2025 was the roughest month in this dataset, with only 62% of arrivals on time. The best was April 2025 at 94%. If your dates are flexible, that 32-point gap is worth planning around.
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Based on 764 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.