Route reliability record
MIA→GSP
Miami to Greer
- Flights
- 724
- Period
- September 2025 to August 2026
- Distance
- 637 mi
- Carriers
- 2
This route lands a B, 2 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 45 minutes on average. That rests on 724 MIA to GSP flights, with a median arrival 7 minutes early.
Best time to fly MIA to GSP: a 8am–11am departure, ideally on a Wednesday. Flights in that window arrived on time 90.9% of the time and Wednesday flights 87.8%, against 79.3% for the route overall.
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
79.3%
Arrivals under 15 minutes late, of 714 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
1.24%
National rate is 1.89%
Best carrier
Envoy
79.7% on time across 698 flights
These figures cover 724 flights between September 2025 and August 2026. The median arrival is 7 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 GSP
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 |
|---|---|---|---|---|---|
| Envoy Air | 698 | 79.7% | 42 min | 1.00% | B |
| Republic Airwaysthin sample | 26 | 66.7% | 111 min | 7.69% | C− |
Flight by flight
Flights on MIA to GSP
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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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 25 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am56 flights90.9%
- 11am–2pm11 flights—
- 2pm–5pm199 flights79.0%
- 5pm–8pm95 flights66.3%
- 8pm–5am363 flights80.7%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 90.9% of the time, against 66.3% for the evening window. That is 25 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 363 flights scheduled in it.
Explore
Filter MIA to GSP 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 GSP, the best departure window is 8am–11am at 90.9% on time and the worst is 5pm–8pm at 66.3%, a wide gap of 24.6 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am90.9%
- 11am–2pm—
- 2–5pm79.0%
- 5–8pm66.3%
- 8pm–5am80.7%
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 32 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.
July is the worst month at 62.1% on time, 32 points below September, the best at 93.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. January was the busiest month here, with 67 flights.
Across the week, Wednesday is the strongest day at 87.8% on time and Sunday the weakest at 66.0%, a spread of 22 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 6,788 reported delay minutes.
- 38%Late-arriving aircraft
- 37%National Airspace System
- 19%Carrier
- 7%Extreme weather
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 6,788 reported delay minutes here, that single category outweighs weather by 6 to one. The split is drawn from 6,788 reported delay minutes.
37% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 2,527 minutes out of 6,788, against a national NAS share of 21%.
Cancellations sit at 1.24% against a national 1.89%, which is ordinary. Diversions add another 0.14%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 4.5% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 637 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 runs 79.2% on time across 723 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 724 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 GSP after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 724 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 79.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 714 completed flights over 12 months sit behind that.
Common questions
MIA to GSP questions
How often is MIA to GSP delayed?
About 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 20.7% of the 724 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 45 minutes on average.
How reliable is MIA to GSP compared with the rest of the country?
79.3% of flights arrive on time here against a national 77.3%, a difference of 2 points 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 GSP?
The 8am–11am departure window is the strongest at 90.9% on time. The 5pm–8pm window is the weakest at 66.3%, 25 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 July delays on MIA to GSP?
July is the weakest month at 62.1% on time, compared with 93.8% in September. Across the year that is 32 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
- GSP to MIA — the return legseparate record
- Miami International (MIA) delay statistics
- MIA to ATL, a related route74.2%
- ATL to GSP, a related route83.7%
- MIA to LGA, a related route67.4%
- Envoy Air on-time record79.7%
- Republic Airways on-time record66.7%
- 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. MIA to GSP and GSP 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.