Route reliability record
STT→MIA
Charlotte Amalie to Miami
- Flights
- 941
- Period
- September 2025 to August 2026
- Distance
- 1,107 mi
- Carriers
- 1
This route lands a B+, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by close to two hours on average. That rests on 941 STT to MIA flights, with a median arrival 16 minutes early.
Best time to fly STT to MIA: a 11am–2pm departure, ideally on a Wednesday. Flights in that window arrived on time 87.2% of the time and Wednesday flights 91.6%, against 81.9% for the route overall.
Set against the rest of the country, this route's record is 5 points better than the US average of 77.3%. That gap is worth roughly 46 fewer late arrivals for every thousand flights.
Key figures
On time
81.9%
Arrivals under 15 minutes late, of 929 completed flights
Avg delay
121 min
Across delayed arrivals only, not all flights
Cancelled
0.74%
National rate is 1.89%
Best carrier
American
81.9% on time across 941 flights
These figures cover 941 flights between September 2025 and August 2026. The median arrival is 16 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 STT to MIA
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 | 81.9% | 121 min | 0.74% | 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–11am—
- 11am–2pm295 flights87.2%
- 2pm–5pm396 flights76.7%
- 5pm–8pm250 flights83.9%
- 8pm–5am—
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 87.2% on time, ahead of 2pm–5pm at 76.7%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 2pm–5pm window is the busiest, with 396 flights scheduled in it.
Explore
Filter STT to MIA 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 STT to MIA, the best departure window is 11am–2pm at 87.2% on time and the worst is 2pm–5pm at 76.7%, a wide gap of 10.5 points. All US flights leaving 11am–2pm ran 78.3%.
- 5–8am—
- 8–11am—
- 11am–2pm87.2%
- 2–5pm76.7%
- 5–8pm83.9%
- 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 21 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.
January is the weak month at 72.8% on time, against 94.0% in May. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. March was the busiest month here, with 124 flights.
Across the week, Wednesday is the strongest day at 91.6% on time and Monday the weakest at 72.8%, a spread of 19 points.
Delay causes
Why this route gets delayed
Carrier accounts for 54% of the 20,000 delay minutes carriers reported here, and the remaining four split what is left.
- 54%Carrier
- 36%Late-arriving aircraft
- 9%National Airspace System
- 0%Extreme weather
- 0%Security
36% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 20,000 reported delay minutes here, that single category outweighs weather by 36 to one. The split is drawn from 20,244 reported delay minutes.
The largest share of delay minutes, 54%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 11,000 of the 20,000 delay minutes reported here.
Cancellations are rare at 0.74%, 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
5.9% 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 close to two hours, 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 78.2% on time across 941 flights, 4 points below 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 MIA 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 81.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 929 completed flights over 12 months sit behind that.
Common questions
STT to MIA questions
How often is STT to MIA delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.1% of the 941 flights in this analysis, against 22.7% nationally. Delayed flights are late by close to two hours on average.
How reliable is STT to MIA compared with the rest of the country?
81.9% of flights arrive on time here against a national 77.3%, a difference of 5 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on STT to MIA?
The 11am–2pm departure window is the strongest at 87.2% on time. The 2pm–5pm window is the weakest at 76.7%, 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 January delays on STT to MIA?
January is the weakest month at 72.8% on time, compared with 94.0% in May. Across the year that is 21 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
- MIA to STT — the return legseparate record
- Miami International (MIA) delay statistics
- STT to ATL, a related route83.0%
- ATL to MIA, a related route71.2%
- LGA to MIA, a related route69.9%
- American Airlines on-time record81.9%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. STT to MIA and MIA to STT 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.