Route reliability record
MIA→STT
Miami to Charlotte Amalie
- Flights
- 941
- Period
- September 2025 to August 2026
- Distance
- 1,107 mi
- Carriers
- 1
This route lands a B+, about a point better than the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 55 minutes on average. That rests on 941 MIA to STT flights, with a median arrival 6 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.2%
Arrivals under 15 minutes late, of 933 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
0.43%
National rate is 1.89%
Best carrier
American
78.2% on time across 941 flights
These figures cover 941 flights between September 2025 and August 2026. The median arrival is 6 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
Which airline is most reliable on MIA to STT
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines | 941 | 78.2% | 53 min | 0.43% | B+ |
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Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 11 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am439 flights84.4%
- 11am–2pm485 flights73.0%
- 2pm–5pm17 flights—
- 5pm–8pm—
- 8pm–5am—
Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 73.0% on time against 84.4% for 8am–11am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 11am–2pm window is the busiest, with 485 flights scheduled in it.
Explore
Filter MIA to STT by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On MIA to STT, the best departure window is 8am–11am at 84.4% on time and the worst is 11am–2pm at 73.0%, a wide gap of 11.4 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am84.4%
- 11am–2pm73.0%
- 2–5pm—
- 5–8pm—
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 27 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
Delays peak in March, when the on-time rate falls to 65.0%. June is the strongest month at 92.2%. Moving a flexible trip across that boundary buys 27 points. March was the busiest month here, with 124 flights.
Across the week, Tuesday is the strongest day at 85.8% on time and Sunday the weakest at 69.9%, a spread of 16 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 11,000 reported delay minutes.
- 39%Carrier
- 28%Late-arriving aircraft
- 27%National Airspace System
- 6%Extreme weather
- 0%Security
The largest share of delay minutes, 39%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,229 of the 11,000 delay minutes reported here. The split is drawn from 10,780 reported delay minutes.
Cancellations are rare at 0.43%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
5.8% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 55 minutes, which a normal layover absorbs.
The 1,107 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 81.9% on time across 941 flights, 4 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 4 points of difference.
One caution: this is a thin sample. 941 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
Work out the risk of missing a connection in STT after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 941 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 78.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 933 completed flights over 12 months sit behind that.
Common questions
MIA to STT questions
How often is MIA to STT delayed?
Roughly one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.8% of the 941 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 55 minutes on average.
How reliable is MIA to STT compared with the rest of the country?
78.2% of flights arrive on time here against a national 77.3%, a difference of about a point in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on MIA to STT?
The 8am–11am departure window is the strongest at 84.4% on time. The 11am–2pm window is the weakest at 73.0%, 11 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are March delays on MIA to STT?
March is the weakest month at 65.0% on time, compared with 92.2% in June. Across the year that is 27 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- STT to MIA — the return legseparate record
- Miami International (MIA) delay statistics
- MIA to ATL, a related route74.2%
- ATL to STT, a related route76.4%
- MIA to LGA, a related route67.4%
- American Airlines on-time record78.2%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. MIA to STT and STT to MIA are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.