Carrier route record

WNMIA→CMH

Southwest Airlines · Miami to Columbus

Flights: 159
Period: July 2025 to June 2026
Share of route: 14%
Carriers: 4

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

Southwest on MIA to CMH draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 159 flights, with a median arrival 7 minutes late.

The national on-time rate over the same period is 77.6%, so Southwest on MIA to CMH runs 16 points behind the country as a whole. Across a thousand flights that is about 161 extra late arrivals.

On time

61.5%

Arrivals under 15 minutes late, of 156 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

1.89%

National rate is 1.81%

Whole route

78.1%

Every carrier on MIA to CMH, 1,119 flights

These figures cover 159 flights between July 2025 and June 2026. Beyond the headline rate, 14.1% 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

Southwest against every carrier on MIA to CMH

Southwest flew 159 of the 1,119 flights on MIA to CMH, about 14% of it. Its 61.5% on time is 17 points worse than the route as a whole, which runs 78.1%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from Republic at 87.5% to Southwest at 61.5%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

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.

On-time performance by carrier on MIA to CMH
Airline	Flights	On time	Avg delay	Cancelled	Grade
Republic Airwaysthin sample	8	87.5%	15 min	0.00%	A+
American Airlinesthin sample	40	87.2%	58 min	2.50%	A
Envoy Air	912	80.5%	51 min	0.11%	B+
Southwest Airlines (this page)thin sample	159	61.5%	58 min	1.89%	D

Departure window

When Southwest runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 14 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am—
8am–11am—
11am–2pm54 flights57.4%
2pm–5pm85 flights71.1%
5pm–8pm20 flights—
8pm–5am—

Scale runs 50% to 75%. 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 57.4% on time against 71.1% for 2pm–5pm. 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 2pm–5pm window is the busiest, with 85 flights scheduled in it.

Across the year

Southwest on MIA to CMH through the year

Jul–Sep 202525 flights—
Oct–Dec 202516 flights—
Jan–Mar 202653 flights48.0%
Apr–Jun 202665 flights69.2%

Scale runs 40% to 75%. 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 61.5% on time across 159 flights.

Split by quarter, Southwest on MIA to CMH logged 25 flights in Jul–Sep 2025, 16 flights in Oct–Dec 2025, 53 flights in Jan–Mar 2026 and 65 flights in Apr–Jun 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 61.5% annual figure is the one to use.

Across the week, Saturday is the strongest day at 55.9% on time and Sunday the weakest at 51.6%. 4 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Southwest runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 57% of the 3,501 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
57%
National Airspace System
24%
Carrier
16%
Extreme weather
3%
Security
1%

57% 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 3,501 reported delay minutes here, that single category outweighs weather by 19 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 3,501 reported delay minutes.

Cancellations sit at 1.89% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

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. 14.1% 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 990 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 is a different operation and performs like one: it runs 82.8% on time across 160 flights, 21 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 21 points of difference.

One caution: this is a thin sample. 159 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 Southwest on MIA to CMH

Put together: treat all of this as provisional. 159 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 61.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 156 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