MIA to BOS flight delays
Miami, FL (MIA) Boston, MA (BOS) · 1,258 miles
3,415 flights · January 2025 – August 2026 · US Bureau of Transportation Statistics
69.67%
Arrived on time
Within 15 minutes of schedule
2.4%
Cancelled
Share of scheduled flights
73 min
When late, late by
Average across delayed arrivals
23 min
Delay per flight
Averaged over every flight flown
What the record says about this route
Which airline you fly changes the odds here. American Airlines arrived on time 16.4 points more often than Spirit Airlines over the same period on the same route — same airports, same weather, same air traffic control. A gap that survives all of that is about how the two airlines are run.
The season swings this route hard. In May it ran 20.5 points more punctual than in October — a difference bigger than the one between the best and worst airlines on most routes. If the date is flexible, it is worth more than the carrier.
The two directions do not behave alike. BOS to MIA arrives on time 8.1 points more often than the outbound. Delay accumulates through the flying day, so whichever direction is scheduled later tends to carry the worse record — which is an argument for booking the morning departure if the choice exists.
Flights from Miami to Boston run late more often than the average route, though not severely.
Which airline should you fly on this route?
Over January 2025 – August 2026, American Airlines arrived on time most often on MIA to BOS. Spirit Airlines was late most often. Flights ran closest to schedule in May and worst in October.
Every airline on MIA to BOS
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| American Airlines | 2,230 | 70.75% | 1.75% | 71 min | D |
| Delta Air Lines | 888 | 70% | 2.93% | 78 min | D |
| Spirit Airlines | 186 | 54.34% | 6.45% | 70 min | F |
| JetBlue Airways | 89 | 66.67% | 5.62% | 68 min | — |
| Republic Airways | 21 | 80.95% | 0% | 96 min | — |
| Envoy Air | 1 | 100% | 0% | — | — |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
BOS to MIA Boston back to Miami 77.73% on time COther routes from Miami
Common questions
Are flights from Miami to Boston usually delayed?
69.67% of flights on the MIA to BOS route arrived within 15 minutes of schedule, so roughly 3 in every ten arrived late. That is worse than the average route in this record.
Which airline is most on time from Miami to Boston?
American Airlines, at 70.75% on time across 2,230 flights. The least punctual on the route was Spirit Airlines at 54.34%.
How often are MIA to BOS flights cancelled?
2.4% of scheduled flights did not operate — about 24 in every thousand. That is in the normal range.
What is the best month to fly Miami to Boston?
May, when 77.4% of flights arrived on time. The worst was October at 56.9%.
When MIA to BOS flights are late, how late are they?
About 73 minutes on average across the flights that arrived more than 15 minutes behind schedule.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on MIA to BOS during January 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →