76% of flights from Boston to Miami arrived on time over the past 12 months. That is about the typical U.S. route. The 5 a.m. departures ran on time 93% of the time; the 5 p.m. ones 56%. Most reliable airline: American Airlines (80%). 11% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for BOS → MIA: when a flight was late, it was under 45 minutes late 51% of the time. About 1 in 12 flights landed an hour or more late, and 1 in 55 three hours or more; 2.2% were cancelled outright.
- On time or early76%
- 15–30 min late7.2%
- 30–60 min late5.9%
- 1–2 hours late4.7%
- 2–3 hours late1.8%
- 3+ hours late1.8%
- Diverted0.2%
- Cancelled2.2%
Share of all 3,368 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| American Airlines | 2,296 | 80% | 1.7% | −12 min | 6.4% | +77 min | American Airlines 99%, Republic Airways 1% |
| Delta Air Lines | 892 | 71% | 2.6% | −2 min | 10.0% | +78 min | Delta Air Lines |
| Spirit Airlines | 176 | 52% | 6.3% | +7 min | 24.4% | +81 min | Spirit Airlines |
| JetBlue | 4 | — | — | — | — | — | JetBlue |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at BOS). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | American Airlines | Delta Air Lines |
|---|---|---|
| 5 a.m. | 93% | — |
| 6 a.m. | 92% | — |
| 7 a.m. | 90% | 82% |
| 8 a.m. | 86% | — |
| 10 a.m. | 78% | — |
| noon | 76% | — |
| 2 p.m. | 64% | — |
| 3 p.m. | 63% | 65% |
| 6 p.m. | 70% | — |
| 7 p.m. | — | 61% |
Last flight of the day
On BOS → MIA, each airline's last flight of the day was cancelled 2.7% of the time, against 1.8% for its earlier flights (1.5× as often). It arrived 3+ hours late 2.3% of the time (earlier flights: 1.7%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| American Airlines | 6:00 p.m. | 2.5% | 1.6% | 1.6% | first flight 5:01 a.m. |
| Delta Air Lines | 3:18 p.m. | 2.5% | 3.0% | 2.7% | first flight 7:20 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
If you need to be in MIA tonight, book an earlier flight so there's a backup if it's cancelled.
By month
Each calendar month pooled over 2023–2026. Best: November (85%). Worst: January (71%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 499 | 73% | 5.4% |
| Tuesday | 469 | 77% | 3.2% |
| Wednesday | 465 | 83% | 0.9% |
| Thursday | 478 | 80% | 0.0% |
| Friday | 487 | 79% | 1.2% |
| Saturday | 483 | 74% | 1.2% |
| Sunday | 487 | 68% | 3.1% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 53 · airline 15 · air traffic/airport 5
Month by month
Flight numbers on this route
Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.
| Flight | Departs | Flights | On time | Cancelled | Typical arrival | Operated by |
|---|---|---|---|---|---|---|
| AA 1418 | 5:00 a.m. | 209 | 95% | 0.0% | −17 min | American Airlines |
| AA 2980 | 6:00 a.m. | 252 | 90% | 2.4% | −21 min | American Airlines |
| AA 873 | 6:00 a.m. | 174 | 89% | 1.1% | −14 min | American Airlines |
| DL 1399 | 7:05 a.m. | 345 | 82% | 2.0% | −7 min | Delta Air Lines |
| AA 1259 | 8:00 a.m. | 311 | 87% | 1.6% | −16 min | American Airlines |
| DL 776 | 3:20 p.m. | 364 | 62% | 1.7% | +3 min | Delta Air Lines |
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Jan 26, 2026 | 11 | 0% | 8 |
| Feb 23, 2026 | 11 | 0% | 11 |
| Apr 7, 2026 | 11 | 9% | 0 |
| Feb 24, 2026 | 11 | 9% | 6 |
| Nov 9, 2025 | 9 | 11% | 4 |
Nearby airport alternatives
Other ways to make the same trip, using airports within 60 miles of Boston or Miami. None has been clearly more reliable than BOS → MIA.
| Route | Flights | On time | Cancelled |
|---|---|---|---|
| BOS → MIA (this route) | 3,368 | 76% | 2.2% |
| PVD → FLL Rhode Island T. F. Green to Fort Lauderdale | 529 | 68% | 1.9% |
| BOS → FLL Boston Logan to Fort Lauderdale | 3,306 | 64% | 3.8% |
Questions
How often are flights from BOS to MIA on time?
76% of 3,368 scheduled flights from Boston, MA to Miami, FL arrived within 15 minutes of schedule between September 2025 and August 2026. 2.2% were cancelled.
What is the best time of day to fly BOS to MIA?
Flights scheduled to leave at 5 a.m. were the most reliable (93% on time). The 5 p.m. departures were the least (56%).
Which airline is most on time from BOS to MIA?
American Airlines: 80% of its 2,296 flights on the route arrived on time. Delta Air Lines: 71%. Spirit Airlines: 52%.
What month has the most delays from BOS to MIA?
January (71% on time). The best month is November (85%), over 2023–2026.
Is the last flight of the day from BOS to MIA more likely to be cancelled?
Yes. Each airline's last BOS–MIA flight of the day was cancelled 2.7% of the time over the past year, against 1.8% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- MIA → BOS (return)
- Boston Logan (BOS) delays by hour
- Flights into Miami (MIA)
- American Airlines on-time record
- Delta Air Lines on-time record
- Spirit Airlines on-time record
- JetBlue on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.