Route reliability record
GSP→MIA
Greer to Miami
- Flights
- 723
- 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 an hour on average. That rests on 723 GSP to MIA flights, with a median arrival 6 minutes early.
Best time to fly GSP to MIA: a 5am–8am departure, ideally on a Monday. Flights in that window arrived on time 87.5% of the time and Monday flights 82.8%, against 79.2% 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
79.2%
Arrivals under 15 minutes late, of 713 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
1.24%
National rate is 1.89%
Best carrier
Envoy
79.5% on time across 697 flights
These figures cover 723 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 GSP 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 |
|---|---|---|---|---|---|
| Envoy Air | 697 | 79.5% | 63 min | 1.00% | B |
| Republic Airwaysthin sample | 26 | 70.8% | 76 min | 7.69% | C− |
Flight by flight
Flights on GSP to MIA
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 30 points, against half a point between the best and worst carrier.
- 5am–8am364 flights87.5%
- 8am–11am15 flights—
- 11am–2pm43 flights83.3%
- 2pm–5pm35 flights82.9%
- 5pm–8pm179 flights71.4%
- 8pm–5am87 flights57.5%
Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 57.5% on time, against 87.5% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 364 flights scheduled in it.
Explore
Filter GSP 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 GSP to MIA, the best departure window is 5am–8am at 87.5% on time and the worst is 8pm–5am at 57.5%, a wide gap of 30.0 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am87.5%
- 8–11am—
- 11am–2pm83.3%
- 2–5pm82.9%
- 5–8pm71.4%
- 8pm–5am57.5%
best all US flightsScale 50% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 37 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 59.7% on time, against 96.9% in September. 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. January was the busiest month here, with 67 flights.
Across the week, Monday is the strongest day at 82.8% on time and Saturday the weakest at 75.0%, a spread of 8 points.
Delay causes
Why this route gets delayed
Carrier accounts for 51% of the 9,441 delay minutes carriers reported here, and the remaining four split what is left.
- 51%Carrier
- 39%Late-arriving aircraft
- 9%National Airspace System
- 2%Extreme weather
39% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 9,441 reported delay minutes here, that single category outweighs weather by 20 to one. The split is drawn from 9,441 reported delay minutes.
The largest share of delay minutes, 51%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,811 of the 9,441 delay minutes reported here.
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
5.0% 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 about an hour, which a normal layover absorbs.
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 79.3% on time across 724 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. 723 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. 723 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 79.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 713 completed flights over 12 months sit behind that.
Common questions
GSP to MIA questions
How often is GSP to MIA 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 20.8% of the 723 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is GSP to MIA compared with the rest of the country?
79.2% 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 GSP to MIA?
The 5am–8am departure window is the strongest at 87.5% on time. The 8pm–5am window is the weakest at 57.5%, 30 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 GSP to MIA?
January is the weakest month at 59.7% on time, compared with 96.9% in September. Across the year that is 37 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 GSP — the return legseparate record
- Miami International (MIA) delay statistics
- GSP to ATL, a related route90.1%
- ATL to MIA, a related route71.2%
- GSP to ORD, a related route75.9%
- Envoy Air on-time record79.5%
- Republic Airways on-time record70.8%
- 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. GSP to MIA and MIA to GSP 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.