Carrier route record

NKMIA→ATL

Spirit Airlines · Miami to Atlanta

Flights: 269
Period: July 2025 to June 2026
Share of route: 4%
Carriers: 6

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Spirit Airlines.

Spirit on MIA to ATL sits in the middle of the pack with a C−. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 269 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 3,300 at 76.7% on time.

Delta Air Lines is the most reliable of the three carriers covered here at 76.7% on time across 3,300 flights.

On time

74.4%

Arrivals under 15 minutes late, of 258 completed flights

Avg delay

71 min

Across delayed arrivals only, not all flights

Cancelled

4.09%

National rate is 1.81%

Whole route

73.7%

Every carrier on MIA to ATL, 6,223 flights

These figures cover 269 flights between July 2025 and June 2026. Beyond the headline rate, 9.3% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

Spirit against every carrier on MIA to ATL

Spirit flew 269 of the 6,223 flights on MIA to ATL, about 4% of it. Its 74.4% on time is about level with the route as a whole at 73.7%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from Envoy at 78.3% to Republic at 65.9%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 76.7% of the time; American Airlines manages 67.5%. Sample sizes sit next to every figure, because a two-point gap across 1,524 flights means less than a ten-point one.

On-time performance by carrier on MIA to ATL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Envoy Airthin sample	225	78.3%	47 min	1.33%	B
Delta Air Lines	3,300	76.7%	83 min	1.39%	B
Spirit Airlines (this page)thin sample	269	74.4%	71 min	4.09%	C−
Frontier Airlines	861	71.8%	79 min	1.86%	C
American Airlines	1,524	67.5%	82 min	0.79%	C+
Republic Airwaysthin sample	44	65.9%	60 min	0.00%	C+

Delta leads American by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Departure window

When Spirit runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am81 flights75.6%
8am–11am30 flights—
11am–2pm89 flights80.9%
2pm–5pm48 flights52.3%
5pm–8pm2 flights—
8pm–5am19 flights—

Scale runs 45% to 85%. Rows with fewer than 30 flights show a dash.

The best window here is not the first bank but the 11am–2pm slot at 80.9% on time, ahead of 2pm–5pm at 52.3%. 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 11am–2pm window is the busiest, with 89 flights scheduled in it.

Across the year

Spirit on MIA to ATL through the year

Jul–Sep 202553 flights71.7%
Oct–Dec 202582 flights87.7%
Jan–Mar 202695 flights63.5%
Apr–Jun 202639 flights74.4%

Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 74.4% on time across 269 flights.

Spirit on MIA to ATL did not run the same all year. Its best quarter was Oct–Dec 2025 at 87.7% on time and its weakest Jan–Mar 2026 at 63.5%, a swing of 24 points on roughly 67 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Monday is the strongest day at 78.9% on time and Sunday the weakest at 66.0%. 13 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Spirit runs late on this route

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 4,688 reported delay minutes.

Late-arriving aircraft
36%
National Airspace System
35%
Carrier
28%
Extreme weather
1%

36% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 4,688 reported delay minutes here, that single category outweighs weather by 25 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 4,688 reported delay minutes.

35% 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 1,628 minutes out of 4,688, against a national NAS share of 21%.

Cancellations run at 4.09%, against 1.81% nationally. That is about one flight in 25 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and stage length

What a delay here costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.3% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

The 594 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg runs 73.3% on time across 269 flights, within about 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. 269 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.

What to do with this

Booking Spirit on MIA to ATL

Put together: the delay figures matter less here than the 4.09% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 11am–2pm departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 258 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures