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DelayAtlas

Carrier performance at one airport

WNCMH

Southwest Airlines at John Glenn Columbus International

Departures
12,353
Period
June 2025 to May 2026
Routes
19
Rank here
#3 of 11
BGRADE

Southwest Airlines at Columbus lands a B, 3 points better than the national rate of 77.4%. About one flight in five arrive 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 12,353 flights, of which Delta Air Lines flew 3,741 at 87.1% on time.

Measured against the airport rather than the country, Southwest Airlines runs about a point ahead of the 79.6% weighted average across all carriers at CMH. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.

Key figures

On time

80.6%

12,191 completed departures

Avg delay

60 min

Across delayed flights only

Cancelled

1.02%

At CMH, this carrier only

Rank here

#3

Of 11 carriers clearing the floor at CMH

These figures cover 12,000 flights between June 2025 and May 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.

Against the competition

Every carrier at CMH, ranked

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 87.1% of the time; Frontier Airlines manages 65.7%. Sample sizes sit next to every figure, because a two-point gap across 477 flights means less than a ten-point one.

On-time performance of all carriers departing CMH
AirlineFlightsOn timeAvg delayCancelledGrade
Delta Air Lines3,74187.1%84 min1.55%A
Republic Airways12,93581.5%66 min3.16%B−
Southwest Airlines (this page)12,35380.6%60 min1.02%B
American Airlines4,10779.9%105 min2.61%B
Envoy Air3,08778.9%82 min0.97%B+
Spirit Airlines1,37274.8%80 min3.72%C−
United Airlines3,26772.6%80 min1.10%C
PSA Airlines1,61872.2%94 min4.26%C−
SkyWest Airlines1,27270.9%111 min3.07%C−
Alaska Airlines46369.6%49 min1.30%C
Frontier Airlines47765.7%83 min2.73%C

PSA Airlines cancels 4.3% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

Route by route

Where Southwest Airlines flies from CMH

Southwest Airlines operates 19 routes out of CMH with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.

Southwest Airlines routes from CMH
RouteFlightsOn timeAvg delayCancelledGrade
CMH to MCO · Orlando1,53580.2%67 min1.11%B
CMH to MDW · Chicago1,26380.8%60 min1.27%B
CMH to BWI · Baltimore1,05587.6%68 min1.90%A
CMH to BNA · Nashville1,00582.7%50 min0.80%B+
CMH to DEN · Denver92477.0%62 min0.54%B+
CMH to TPA · Tampa90484.0%54 min1.00%B
CMH to LAS · Las Vegas84079.6%58 min0.48%B+
CMH to STL · St. Louis67283.7%66 min0.74%B+
CMH to RSW · Fort Myers64780.1%65 min1.55%B
CMH to PHX · Phoenix57582.2%61 min1.22%B
CMH to DAL · Dallas49478.2%48 min1.42%B
CMH to FLL · Fort Lauderdale39975.8%59 min0.75%B+
CMH to AUS · Austinthin sample35780.3%57 min0.28%B+
CMH to HOU · Houstonthin sample35483.3%64 min0.28%B+
CMH to DCA · Washingtonthin sample35160.4%67 min1.14%D
CMH to ATL · Atlantathin sample33282.7%45 min0.90%B+
CMH to SRQ · Sarasotathin sample28677.7%59 min1.05%B
CMH to MIA · Miamithin sample16084.1%57 min1.25%B
CMH to SAN · San Diegothin sample14468.5%39 min0.69%C+

Departure window

Best time of day for this operation

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 31 points, against 21 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am3,284 flights94.8%
  • 8am–11am1,446 flights90.8%
  • 11am–2pm2,017 flights82.5%
  • 2pm–5pm2,241 flights71.6%
  • 5pm–8pm2,340 flights68.7%
  • 8pm–5am1,025 flights63.5%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 63.5% on time, against 94.8% 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.

Across the year

Seasonal pattern

On-time rate by calendar month87J83F76M83A79M77J74J85A88S84O82N75D
Darker means more delays. Figures are on-time percentages.September best, July worst

July is the worst month at 73.6% on time, 14 points below September, the best at 87.8%. 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.

Delay causes

What holds this operation up

  • Late-arriving aircraft
    52%
  • National Airspace System
    23%
  • Carrier
    23%
  • Extreme weather
    2%
  • Security
    0%

52% 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 142,000 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.

Cancellations sit at 1.02% against a national 1.80%, which is ordinary. Diversions add another 0.29%.

6.1% of arrivals land an hour or more late, close to the national 8.2%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the about an hour kind, which a normal layover absorbs.

12,353 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 87.8% on time and July 73.6%, a swing of 14 points. If the dates move at all, move them out of July before you think about anything else.

Common questions

Southwest Airlines at CMH

How often is Southwest Airlines at CMH delayed?

About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.4% of the 12,353 flights in this analysis, against 22.6% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on Southwest Airlines at CMH?

Delta Air Lines leads at 87.1% on time across 3,741 flights. Frontier Airlines is at the other end on 65.7%, a gap of 21 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on Southwest Airlines at CMH?

The 5am–8am departure window is the strongest at 94.8% on time. The 8pm–5am window is the weakest at 63.5%, 31 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 Southwest Airlines at CMH?

July is the weakest month at 73.6% on time, compared with 87.8% in September. Across the year that is 14 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

Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.