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DelayAtlas

Carrier performance at one airport

WNCMH

Southwest Airlines at John Glenn Columbus International

Departures
12,324
Period
July 2025 to June 2026
Routes
19
Rank here
#4 of 11
BGRADE

Southwest Airlines at Columbus lands a B, 3 points better than the national rate of 77.6%. 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 12,324 flights, of which Delta Air Lines flew 3,727 at 87.7% on time.

Measured against the airport rather than the country, Southwest Airlines runs half a point ahead of the 80.1% 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

80.5%

12,158 completed departures

Avg delay

59 min

Across delayed flights only

Cancelled

1.02%

At CMH, this carrier only

Rank here

#4

Of 11 carriers clearing the floor at CMH

These figures cover 12,000 flights between July 2025 and June 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 87.7% of the time; Frontier Airlines manages 65.4%. Sample sizes sit next to every figure, because a two-point gap across 500 flights means less than a ten-point one.

On-time performance of all carriers departing CMH
AirlineFlightsOn timeAvg delayCancelledGrade
Delta Air Lines3,72787.7%87 min1.40%A
Republic Airways13,05382.0%66 min3.05%B−
American Airlines4,14680.8%105 min2.46%B
Southwest Airlines (this page)12,32480.5%59 min1.02%B
Envoy Air3,08779.9%86 min1.07%B
PSA Airlines1,62375.1%88 min3.94%B−
Spirit Airlines1,16374.2%78 min3.53%C−
SkyWest Airlines1,28473.2%110 min3.19%C−
United Airlines3,27572.9%82 min1.19%C
Alaska Airlines46070.9%49 min1.30%C
Frontier Airlines50065.4%85 min2.20%C

PSA Airlines cancels 3.9% 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 · Orlando1,52480.0%65 min1.05%B
CMH to MDW · Chicago1,25180.8%60 min1.44%B
CMH to BWI · Baltimore1,05187.4%67 min1.90%A
CMH to BNA · Nashville1,02283.1%51 min0.78%B+
CMH to DEN · Denver92278.4%62 min0.54%B+
CMH to TPA · Tampa90284.1%54 min1.00%B
CMH to LAS · Las Vegas83979.2%58 min0.48%B+
CMH to STL · St. Louis67284.3%67 min0.74%B+
CMH to RSW · Fort Myers65179.8%65 min1.54%B
CMH to PHX · Phoenix55680.3%57 min1.08%B
CMH to DAL · Dallas51378.4%48 min1.36%B
CMH to FLL · Fort Lauderdale38677.5%55 min0.78%B+
CMH to AUS · Austinthin sample35682.5%53 min0.28%B+
CMH to HOU · Houstonthin sample35481.9%61 min0.28%B+
CMH to DCA · Washingtonthin sample35160.2%67 min1.14%D
CMH to ATL · Atlantathin sample32681.7%46 min0.92%B+
CMH to SRQ · Sarasotathin sample26176.0%57 min1.15%B
CMH to SAN · San Diegothin sample16861.7%39 min0.60%D+
CMH to MIA · Miamithin sample16082.8%55 min1.25%B

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 30 points, against 22 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–11am1,443 flights90.9%
  • 11am–2pm2,069 flights81.7%
  • 2pm–5pm2,218 flights70.6%
  • 5pm–8pm2,308 flights68.8%
  • 8pm–5am1,002 flights64.7%

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

The 8pm–5am window is where this operation falls apart: 64.7% 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. The 5am–8am window is the busiest, with 3,284 flights scheduled in it.

Across the year

Seasonal pattern

On-time rate by calendar month87J83F76M83A79M76J74J85A88S84O82N75D
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. March was the busiest month here, with 1,224 flights.

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 139,000 reported delay minutes here, that single category outweighs weather by 27 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 139,310 reported delay minutes.

Cancellations sit at 1.02% against a national 1.81%, which is ordinary. Diversions add another 0.32%.

5.9% of arrivals land an hour or more late, close to the national 8.1%. 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.

12,324 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. 12,158 completed flights over 12 months sit behind that.

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 19.5% of the 12,324 flights in this analysis, against 22.4% 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 87.7% on time across 3,727 flights. Frontier Airlines is at the other end on 65.4%, a gap of 22 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 64.7%, 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 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, July 2025 to June 2026. Updated monthly. How this data is collected.