Carrier performance at one airport
WN→ATL
Southwest Airlines at Hartsfield-Jackson Atlanta International
- Departures
- 17,133
- Period
- September 2025 to August 2026
- Routes
- 21
- Rank here
- #5 of 12
Southwest Airlines at Atlanta lands a B, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 17,133 flights, of which United Airlines flew 7,672 at 79.7% on time.
Measured against the airport rather than the country, Southwest Airlines runs about a point behind the 77.8% weighted average across all carriers at ATL. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
76.4%
16,862 completed departures
Avg delay
59 min
Across delayed flights only
Cancelled
1.10%
At ATL, this carrier only
Rank here
#5
Of 12 carriers clearing the floor at ATL
These figures cover 17,000 flights between September 2025 and August 2026. The median arrival is 3 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 ATL, ranked
The choice of carrier is not cosmetic here. United Airlines arrives on time 79.7% of the time; Frontier Airlines manages 63.7%. Sample sizes sit next to every figure, because a two-point gap across 20,778 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 7,672 | 79.7% | 84 min | 1.51% | B |
| Delta Air Lines | 240,917 | 79.5% | 59 min | 1.67% | B |
| Alaska Airlines | 1,359 | 78.7% | 54 min | 0.81% | B+ |
| PSA Airlines | 3,319 | 77.6% | 110 min | 5.33% | B− |
| Southwest Airlines (this page) | 17,133 | 76.4% | 59 min | 1.10% | B |
| American Airlines | 6,907 | 75.7% | 106 min | 1.90% | B |
| SkyWest Airlines | 6,699 | 75.1% | 106 min | 2.58% | B |
| Republic Airways | 3,135 | 74.9% | 84 min | 4.85% | C− |
| Envoy Air | 1,064 | 72.1% | 69 min | 2.54% | C |
| Spirit Airlines | 3,886 | 70.7% | 77 min | 4.01% | C− |
| JetBlue Airways | 2,858 | 69.1% | 89 min | 4.55% | C− |
| Frontier Airlines | 20,778 | 63.7% | 83 min | 2.42% | D |
PSA Airlines cancels 5.3% 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 ATL
Southwest Airlines operates 21 routes out of ATL 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.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| ATL to BWI · Baltimore | 1,555 | 77.0% | 61 min | 1.93% | B |
| ATL to MDW · Chicago | 1,538 | 73.7% | 62 min | 1.56% | C |
| ATL to DAL · Dallas | 1,498 | 76.6% | 58 min | 1.67% | B |
| ATL to HOU · Houston | 1,461 | 79.5% | 60 min | 0.82% | B+ |
| ATL to STL · St. Louis | 1,095 | 79.0% | 57 min | 0.37% | B+ |
| ATL to MCO · Orlando | 1,095 | 74.5% | 60 min | 1.19% | C |
| ATL to DCA · Washington | 1,076 | 70.4% | 67 min | 1.67% | C |
| ATL to DEN · Denver | 1,071 | 73.5% | 57 min | 1.21% | C |
| ATL to AUS · Austin | 1,038 | 82.4% | 52 min | 0.58% | B+ |
| ATL to BNA · Nashville | 889 | 76.0% | 69 min | 0.56% | B+ |
| ATL to TPA · Tampa | 731 | 75.1% | 64 min | 0.82% | B+ |
| ATL to LAS · Las Vegas | 719 | 76.4% | 49 min | 0.42% | B+ |
| ATL to LGA · New York | 700 | 72.0% | 65 min | 2.86% | C |
| ATL to PHX · Phoenix | 572 | 72.0% | 55 min | 0.35% | C+ |
| ATL to MCI · Kansas City | 365 | 79.7% | 47 min | 0.00% | B+ |
| ATL to MSY · New Orleansthin sample | 342 | 77.9% | 49 min | 0.29% | B+ |
| ATL to IND · Indianapolisthin sample | 313 | 78.5% | 47 min | 0.32% | B+ |
| ATL to CMH · Columbusthin sample | 309 | 75.8% | 52 min | 0.65% | B+ |
| ATL to SAT · San Antoniothin sample | 292 | 82.1% | 46 min | 0.34% | B+ |
| ATL to PIT · Pittsburghthin sample | 285 | 79.2% | 55 min | 0.35% | B+ |
| ATL to RDU · Raleighthin sample | 185 | 88.5% | 65 min | 1.08% | A |
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 42 points, against 16 points between the best and worst carrier.
- 5am–8am2,760 flights93.3%
- 8am–11am2,415 flights86.2%
- 11am–2pm3,205 flights84.2%
- 2pm–5pm3,909 flights73.3%
- 5pm–8pm3,618 flights61.6%
- 8pm–5am1,226 flights51.6%
Scale runs 45% to 100%.
The 8pm–5am window is where this operation falls apart: 51.6% on time, against 93.3% 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 2pm–5pm window is the busiest, with 3,909 flights scheduled in it.
Across the year
Seasonal pattern
July is the worst month at 64.0% on time, 24 points below January, the best at 88.4%. 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. October was the busiest month here, with 1,624 flights.
Delay causes
What holds this operation up
- 50%Late-arriving aircraft
- 27%Carrier
- 19%National Airspace System
- 3%Extreme weather
- 1%Security
50% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 235,000 reported delay minutes here, that single category outweighs weather by 16 to one. The split is drawn from 234,744 reported delay minutes.
Cancellations sit at 1.10% against a national 1.89%, which is ordinary. Diversions add another 0.48%.
7.4% of arrivals land an hour or more late, close to the national 8.3%, so 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.
17,133 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. January runs 88.4% on time and July 64.0%, a swing of 24 points. If the dates move at all, move them out of July before you think about anything else. 16,862 completed flights over 12 months sit behind that.
Common questions
Southwest Airlines at ATL
How often is Southwest Airlines at ATL delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.6% of the 17,133 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on Southwest Airlines at ATL?
United Airlines leads at 79.7% on time across 7,672 flights. Frontier Airlines is at the other end on 63.7%, a gap of 16 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 ATL?
The 5am–8am departure window is the strongest at 93.3% on time. The 8pm–5am window is the weakest at 51.6%, 42 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 ATL?
July is the weakest month at 64.0% on time, compared with 88.4% in January. Across the year that is 24 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
- Southwest Airlines network-wide record
- Hartsfield-Jackson Atlanta International (ATL) all carriers
- ATL to BWI route record77.0%
- ATL to MDW route record73.7%
- ATL to DAL route record76.6%
- ATL to HOU route record79.5%
- Why the first flight of the morning is statistically safest
- Do airlines run better at their own hubs?
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.