Carrier route record

WNCMH→MIA

Southwest Airlines · Columbus to Miami

Flights: 160
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 CMH to MIA lands a B, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That is a workable record, not a spotless one. That rests on 160 flights, with a median arrival 4 minutes early.

Set against the rest of the country, Southwest's CMH to MIA record is 5 points better than the US average of 77.6%. That gap is worth roughly 52 fewer late arrivals for every thousand flights.

On time

82.8%

Arrivals under 15 minutes late, of 157 completed flights

Avg delay

55 min

Across delayed arrivals only, not all flights

Cancelled

1.25%

National rate is 1.81%

Whole route

82.3%

Every carrier on CMH to MIA, 1,121 flights

These figures cover 160 flights between July 2025 and June 2026. The median arrival is 4 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.

Carrier by carrier

Southwest against every carrier on CMH to MIA

Southwest flew 160 of the 1,121 flights on CMH to MIA, about 14% of it. Its 82.8% on time is about level with the route as a whole at 82.3%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from Republic at 100.0% to Envoy at 82.0%. 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 CMH to MIA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Republic Airwaysthin sample	2	100.0%	—	0.00%	A+
American Airlinesthin sample	41	87.5%	112 min	2.44%	A
Southwest Airlines (this page)thin sample	160	82.8%	55 min	1.25%	B
Envoy Air	918	82.0%	68 min	0.11%	B+

Departure window

When Southwest runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 160 flights.

5am–8am11 flights—
8am–11am71 flights85.5%
11am–2pm55 flights79.6%
2pm–5pm23 flights—
5pm–8pm—
8pm–5am—

Scale runs 70% to 90%. 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 79.6% on time against 85.5% for 8am–11am. 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 8am–11am window is the busiest, with 71 flights scheduled in it.

Across the year

Southwest on CMH to MIA through the year

Jul–Sep 202525 flights—
Oct–Dec 202516 flights—
Jan–Mar 202654 flights80.8%
Apr–Jun 202665 flights89.2%

Scale runs 70% 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 82.8% on time across 160 flights.

Split by quarter, Southwest on CMH to MIA logged 25 flights in Jul–Sep 2025, 16 flights in Oct–Dec 2025, 54 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 82.8% annual figure is the one to use.

Across the week, Sunday is the strongest day at 87.1% on time and Saturday the weakest at 80.0%. 7 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Southwest 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 1,481 reported delay minutes.

Late-arriving aircraft
41%
Carrier
35%
National Airspace System
24%

41% 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 1,481 reported delay minutes here, that single category outweighs weather by 41 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 1,481 reported delay minutes.

The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 518 of the 1,481 delay minutes reported here.

Cancellations sit at 1.25% against a national 1.81%, which is ordinary. Diversions add another 0.62%.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 3.8% land an hour or more behind schedule, against 8.1% 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 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 61.5% on time across 159 flights, 21 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 21 points of difference.

One caution: this is a thin sample. 160 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 CMH to MIA

Put together: treat all of this as provisional. 160 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 82.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 157 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