Best Time to Fly MIA to BOS: On-Time Stats by Hour & Airline
Miami International → Logan International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 69.9% of Miami (MIA) to Boston (BOS) flights arrived on time (3,381 scheduled flights). That is 7.7 points below the national average of 77.6%.
Among 4 airlines, JetBlue led with 74.3% on time and Spirit Airlines was last with 55.0%.
Over 24 months, Wednesday was the most reliable day (77% on time) and July the worst month (61%).
The cancellation rate was 2.2% (US average 1.8%).
MIA 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 |
|---|---|---|---|---|
| JetBlue | 74.3% | 44 min | 0.0% | 35 |
| Delta Air Lines | 70.7% | 79 min | 2.8% | 889 |
| American Airlines | 70.6% | 72 min | 1.7% | 2,251 |
| Spirit Airlines | 55.0% | 69 min | 6.5% | 184 |
| Envoy Air | Limited data | 1 | ||
| Republic Airways | Limited data | 21 | ||
80%+ good 70–79.9% fair <70% poor
Best time of day to fly MIA to BOS
On-time arrival % by scheduled departure hour (local time), 7,359 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | 92.0% | 0.0% | 50 |
| 6am–7am | 88.9% | 2.1% | 425 |
| 7am–8am | 85.4% | 2.4% | 212 |
| 8am–9am | 91.8% | 0.9% | 673 |
| 9am–10am | 81.2% | 0.0% | 69 |
| 10am–11am | 80.5% | 1.9% | 423 |
| 11am–12pm | 74.8% | 1.0% | 1,005 |
| 12pm–1pm | 66.6% | 1.6% | 606 |
| 1pm–2pm | 68.1% | 2.5% | 122 |
| 2pm–3pm | 65.8% | 2.3% | 308 |
| 3pm–4pm | 66.0% | 1.2% | 161 |
| 4pm–5pm | 74.0% | 1.1% | 178 |
| 5pm–6pm | 59.4% | 1.5% | 524 |
| 6pm–7pm | 63.6% | 1.1% | 264 |
| 7pm–8pm | 61.1% | 2.4% | 941 |
| 8pm–9pm | 61.3% | 3.5% | 647 |
| 9pm–10pm | 67.5% | 2.3% | 747 |
| 10pm–11pm | Limited data | 3 | |
| 11pm–12am | Limited data | 1 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on MIA 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) | 79.8% | +6.8 pts | 0.0% | 134 |
| Christmas & New Year (Dec 20 - Jan 3) | 66.2% | -6.9 pts | 3.2% | 339 |
| Summer peak (Jun 15 - Aug 15) | 64.0% | -9.0 pts | 2.8% | 1,142 |
| All other days | 73.0% | — | 1.6% | 5,744 |
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).