Best Time to Fly SJU to BOS: On-Time Stats by Hour & Airline
Luis Munoz Marin International → Logan International
Data through July 2026 · Last updated October 18, 2026
1,961 flights were scheduled from San Juan (SJU) to Boston (BOS) in the last 12 months, and 71.0% of those that flew arrived on time, 6.6 points below the US average of 77.6%.
Delta Air Lines was the most punctual of the 4 airlines on the route at 77.3%, while JetBlue trailed at 69.0%.
June has been the best month (83% on time) and Saturday the weakest day of the week (71%).
3.1% of flights were cancelled, versus 1.8% nationally.
SJU to BOS on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| Delta Air Lines | 77.3% | 68 min | 1.5% | 398 |
| Spirit Airlines | 73.2% | 58 min | 4.1% | 145 |
| Frontier Airlines | 69.7% | 45 min | 2.9% | 34 |
| JetBlue | 69.0% | 76 min | 3.5% | 1,384 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly SJU to BOS
On-time arrival % by scheduled departure hour (local time), 4,146 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 12am–1am | 93.5% | 0.0% | 31 |
| 1am–2am | Limited data | 2 | |
| 2am–3am | 80.5% | 2.4% | 42 |
| 3am–4am | Limited data | 15 | |
| 4am–5am | Limited data | 4 | |
| 5am–6am | 88.3% | 2.5% | 245 |
| 6am–7am | 76.4% | 2.1% | 376 |
| 7am–8am | 77.9% | 1.4% | 147 |
| 8am–9am | 80.4% | 0.0% | 206 |
| 9am–10am | 72.9% | 2.0% | 50 |
| 10am–11am | 85.3% | 2.1% | 97 |
| 11am–12pm | 75.9% | 4.4% | 91 |
| 12pm–1pm | 67.0% | 1.1% | 276 |
| 1pm–2pm | 78.9% | 1.0% | 625 |
| 2pm–3pm | 77.3% | 1.6% | 565 |
| 3pm–4pm | 61.4% | 3.9% | 362 |
| 4pm–5pm | 73.7% | 2.0% | 151 |
| 5pm–6pm | 60.2% | 4.2% | 168 |
| 6pm–7pm | 65.2% | 3.7% | 161 |
| 7pm–8pm | 63.4% | 2.5% | 238 |
| 8pm–9pm | 66.3% | 4.4% | 181 |
| 9pm–10pm | 55.3% | 0.0% | 76 |
| 10pm–11pm | Limited data | 17 | |
| 11pm–12am | Limited data | 20 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on SJU to BOS
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 75.0% | +0.6 pts | 2.7% | 74 |
| Christmas & New Year (Dec 20 - Jan 3) | 59.5% | -14.9 pts | 4.6% | 261 |
| Summer peak (Jun 15 - Aug 15) | 73.4% | -1.0 pts | 3.5% | 693 |
| All other days | 74.4% | — | 1.5% | 3,118 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).