Boston (BOS) to Miami (MIA): On-Time Performance
Data through July 2026
When you fly BOS to MIA matters as much as anything else about the booking: the route swung from 91% on-time in November 2024 to just 70% in December 2025. Across the full period the route averages 78% on-time against a national 78%. Morning departures also hold up better than evening ones (86% vs 67%), which matters most in the rough months.
- On-time
- 78%
- arrived <15 min late
- Avg delay
- 17 min
- completed flights
- Cancelled
- 1.7%
- Flights/day
- 9.3
- last 12 months
- Duration
- 3h 39m
- scheduled
- Distance
- 1,258 mi
Best airline from BOS to MIA
5 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| American Airlinesmost reliable | 82% | 13 min | 1.5% | 4,714 |
| Delta Air Lines | 74% | 22 min | 2.1% | 1,670 |
| Frontier Airlines | 71% | 18 min | 0.0% | 70 |
| JetBlue Airways | 69% | 21 min | 1.6% | 684 |
| Spirit Airlines | 65% | 30 min | 2.9% | 452 |
Monthly on-time trend
Best time to fly from BOS to MIA
Aim for departures around 5 a.m. (94% on-time); avoid 8 p.m. departures (58%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 77% | 20 min |
| Tuesday | 81% | 17 min |
| Wednesdaybest | 82% | 13 min |
| Thursday | 78% | 17 min |
| Friday | 79% | 17 min |
| Saturday | 78% | 15 min |
| Sunday | 72% | 20 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft31%
- Airline operations37%
- National airspace system30%
- Weather2%
Frequently asked questions
- How often are flights from BOS to MIA delayed?
- 22% of BOS–MIA 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 17 minutes.
- Which airline is most reliable from BOS to MIA?
- American Airlines has the best on-time record on this route at 82%, based on 4,714 flights. 5 airlines flew BOS–MIA frequently enough to compare in this period.
- What is the best time of day to fly from BOS to MIA?
- Departures around 5 a.m. have the best record (94% on-time), while departures around 8 p.m. have the worst (58%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from BOS to MIA?
- The scheduled BOS–MIA flight time averages 3h 39m over 1,258 miles. Actual arrival times vary — flights on this route land 15+ minutes late 22% of the time.
- How often are BOS to MIA flights cancelled?
- 1.7% 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 BOS to MIA?
- December 2025 was the roughest month in this dataset, with only 70% of arrivals on time. The best was November 2024 at 91%. If your dates are flexible, that 21-point gap is worth planning around.
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Based on 7,637 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.