Carrier route record

WNHOU→ATL

Southwest Airlines · Houston to Atlanta

Flights: 1,501
Period: July 2025 to June 2026
Share of route: 51%
Carriers: 2

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

Southwest on HOU to ATL sits in the middle of the pack with a B+. 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 roughly 50 minutes behind schedule. That rests on 1,501 flights, with a median arrival 1 minute early.

The US average over the same twelve months is 77.6%, so there is little to separate Southwest on HOU to ATL from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

75.1%

Arrivals under 15 minutes late, of 1,492 completed flights

Avg delay

49 min

Across delayed arrivals only, not all flights

Cancelled

0.53%

National rate is 1.81%

Whole route

79.8%

Every carrier on HOU to ATL, 2,917 flights

These figures cover 1,501 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

Carrier by carrier

Southwest against every carrier on HOU to ATL

Southwest flew 1,501 of the 2,917 flights on HOU to ATL, most of the route. Its 75.1% on time is 5 points worse than the route as a whole, which runs 79.8%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Delta at 84.9% to Southwest at 75.1%.

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 HOU to ATL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	1,416	84.9%	97 min	1.77%	B
Southwest Airlines (this page)	1,501	75.1%	49 min	0.53%	B+

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 42 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–8am80 flights96.2%
8am–11am321 flights85.9%
11am–2pm287 flights84.6%
2pm–5pm308 flights72.3%
5pm–8pm366 flights64.3%
8pm–5am139 flights54.0%

Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 54.0% on time, against 96.2% 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 5pm–8pm window is the busiest, with 366 flights scheduled in it.

Across the year

Southwest on HOU to ATL through the year

Darker means more delays. Figures are on-time percentages.September best, March worst

September is the best month on the calendar at 90.7% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 136 flights.

Across the week, Friday is the strongest day at 77.5% on time and Sunday the weakest at 70.4%. 7 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 48% of the 18,000 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
48%
Carrier
35%
National Airspace System
14%
Extreme weather
3%
Security
0%

48% 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 18,000 reported delay minutes here, that single category outweighs weather by 16 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 18,015 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 6,224 of the 18,000 delay minutes reported here.

Cancellations are rare at 0.53%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

6.3% 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 last roughly 50 minutes, which a normal layover absorbs.

The 696 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 79.9% on time across 1,499 flights, 5 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 5 points of difference.

The sample behind these figures is 1,501 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking Southwest on HOU to ATL

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 90.7% on time and March 53.8%, a swing of 37 points. If the dates move at all, move them out of March before you think about anything else. 1,492 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