Carrier route record
WNATL→HOU
Southwest Airlines · Atlanta to Houston
- Flights
- 1,499
- 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 ATL to HOU lands a B+, 2 points better than the national rate of 77.6%. About one flight in five arrives 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 1,499 flights, with a median arrival 7 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Southwest on ATL to HOU from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
79.9%
Arrivals under 15 minutes late, of 1,485 completed flights
Avg delay
58 min
Across delayed arrivals only, not all flights
Cancelled
0.67%
National rate is 1.81%
Whole route
80.5%
Every carrier on ATL to HOU, 2,915 flights
These figures cover 1,499 flights between July 2025 and June 2026. The median arrival is 7 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 ATL to HOU
Southwest flew 1,499 of the 2,915 flights on ATL to HOU, most of the route. Its 79.9% on time is about level with the route as a whole at 80.5%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Delta at 81.2% to Southwest at 79.9%.
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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,416 | 81.2% | 56 min | 1.77% | B |
| Southwest Airlines (this page) | 1,499 | 79.9% | 58 min | 0.67% | 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 33 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–8am326 flights93.2%
- 8am–11am173 flights87.8%
- 11am–2pm309 flights88.3%
- 2pm–5pm221 flights79.5%
- 5pm–8pm346 flights63.2%
- 8pm–5am124 flights60.2%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 60.2% on time, against 93.2% 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 346 flights scheduled in it.
Across the year
Southwest on ATL to HOU through the year
Delays peak in May, when the on-time rate falls to 71.9%. February is the strongest month at 91.2%. Moving a flexible trip across that boundary buys 19 points. July was the busiest month here, with 136 flights.
Across the week, Wednesday is the strongest day at 87.6% on time and Monday the weakest at 75.8%. 12 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 55% of the 17,000 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.
- 55%Late-arriving aircraft
- 27%Carrier
- 14%National Airspace System
- 4%Extreme weather
- 1%Security
55% 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 17,000 reported delay minutes here, that single category outweighs weather by 15 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 17,263 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 93.2% on time here.
Cancellations are rare at 0.67%, 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
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 last about an hour, 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 75.1% on time across 1,501 flights, 5 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 5 points of difference.
The sample behind these figures is 1,499 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 ATL to HOU
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 91.2% on time and May 71.9%, a swing of 19 points. If the dates move at all, move them out of May before you think about anything else. 1,485 completed flights over 12 months sit behind that.
Related
Where to go next
- ATL to HOU, every carrier
- Southwest on HOU to ATL, the return leg
- Delta Air Lines on ATL to HOU81.2%
- Southwest Airlines network-wide record
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- William P. Hobby (HOU) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.