Miami (MIA) to Boston (BOS): On-Time Performance
Data through July 2026
When you fly MIA to BOS matters as much as anything else about the booking: the route swung from 85% on-time in November 2024 to just 57% in October 2025. Across the full period the route averages 71% on-time against a national 78%. Morning departures also hold up better than evening ones (83% vs 62%), which matters most in the rough months.
- On-time
- 71%
- arrived <15 min late
- Avg delay
- 23 min
- completed flights
- Cancelled
- 1.9%
- Flights/day
- 9.3
- last 12 months
- Duration
- 3h 24m
- scheduled
- Distance
- 1,258 mi
Best airline from MIA to BOS
5 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| Frontier Airlinesmost reliable | 90% | 9 min | 0.0% | 70 |
| American Airlines | 72% | 21 min | 1.5% | 4,714 |
| Delta Air Lines | 69% | 28 min | 2.3% | 1,668 |
| Spirit Airlines | 68% | 23 min | 3.5% | 451 |
| JetBlue Airways | 67% | 26 min | 2.3% | 682 |
Monthly on-time trend
Best time to fly from MIA to BOS
Aim for departures around 5 a.m. (92% on-time); avoid 5 p.m. departures (59%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 68% | 29 min |
| Tuesday | 74% | 21 min |
| Wednesdaybest | 76% | 18 min |
| Thursday | 70% | 21 min |
| Friday | 71% | 21 min |
| Saturday | 75% | 20 min |
| Sunday | 65% | 28 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft40%
- Airline operations34%
- National airspace system23%
- Weather4%
Frequently asked questions
- How often are flights from MIA to BOS delayed?
- 29% of MIA–BOS 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 23 minutes.
- Which airline is most reliable from MIA to BOS?
- Frontier Airlines has the best on-time record on this route at 90%, based on 70 flights. 5 airlines flew MIA–BOS frequently enough to compare in this period.
- What is the best time of day to fly from MIA to BOS?
- Departures around 5 a.m. have the best record (92% on-time), while departures around 5 p.m. have the worst (59%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from MIA to BOS?
- The scheduled MIA–BOS flight time averages 3h 24m over 1,258 miles. Actual arrival times vary — flights on this route land 15+ minutes late 29% of the time.
- How often are MIA to BOS flights cancelled?
- 1.9% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, slightly above the national rate of 1.6%.
- What is the worst month to fly from MIA to BOS?
- October 2025 was the roughest month in this dataset, with only 57% of arrivals on time. The best was November 2024 at 85%. If your dates are flexible, that 29-point gap is worth planning around.
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Based on 7,633 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.