Carrier performance at one airport
WN→ATL
Southwest Airlines at Hartsfield-Jackson Atlanta International
- Departures
- 18,107
- Period
- June 2025 to May 2026
- Routes
- 21
- Rank here
- #5 of 12
Southwest Airlines at Atlanta lands a B, level with the national rate of 77.4%. About one flight in four 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 18,107 flights, of which United Airlines flew 7,431 at 80.3% on time.
Measured against the airport rather than the country, Southwest Airlines runs half a point behind the 77.0% 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
76.8%
17,838 completed departures
Avg delay
60 min
Across delayed flights only
Cancelled
1.17%
At ATL, this carrier only
Rank here
#5
Of 12 carriers clearing the floor at ATL
These figures cover 18,000 flights between June 2025 and May 2026. The median arrival is 4 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 80.3% of the time; Frontier Airlines manages 63.2%. Sample sizes sit next to every figure, because a two-point gap across 19,091 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 7,431 | 80.3% | 83 min | 1.44% | B |
| PSA Airlines | 3,194 | 78.8% | 108 min | 4.82% | B− |
| Delta Air Lines | 241,168 | 78.4% | 60 min | 1.72% | B |
| Republic Airways | 2,717 | 77.0% | 77 min | 4.05% | B− |
| Southwest Airlines (this page) | 18,107 | 76.8% | 60 min | 1.17% | B |
| American Airlines | 6,851 | 75.9% | 107 min | 2.07% | B |
| Alaska Airlines | 1,463 | 75.4% | 57 min | 0.75% | B+ |
| SkyWest Airlines | 7,416 | 73.7% | 108 min | 2.17% | C |
| Envoy Air | 1,153 | 72.7% | 69 min | 3.12% | C− |
| Spirit Airlines | 6,049 | 70.5% | 75 min | 2.89% | C |
| JetBlue Airways | 2,469 | 70.5% | 92 min | 3.52% | C− |
| Frontier Airlines | 19,091 | 63.2% | 83 min | 2.33% | D |
PSA Airlines cancels 4.8% 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 | 1,577 | 78.2% | 67 min | 2.47% | B |
| ATL to DAL · Dallas | 1,573 | 77.1% | 58 min | 1.65% | B |
| ATL to MDW · Chicago | 1,550 | 76.9% | 55 min | 1.35% | B |
| ATL to HOU · Houston | 1,517 | 78.8% | 61 min | 0.66% | B+ |
| ATL to DCA · Washington | 1,169 | 73.0% | 72 min | 1.71% | C |
| ATL to STL · St. Louis | 1,153 | 80.4% | 60 min | 0.78% | B+ |
| ATL to MCO · Orlando | 1,095 | 75.2% | 62 min | 1.10% | B |
| ATL to DEN · Denver | 1,083 | 72.5% | 59 min | 1.29% | C |
| ATL to LGA · New York | 1,051 | 68.7% | 71 min | 2.85% | C |
| ATL to AUS · Austin | 1,036 | 80.6% | 51 min | 0.58% | B+ |
| ATL to BNA · Nashville | 866 | 80.6% | 64 min | 0.46% | B+ |
| ATL to TPA · Tampa | 732 | 74.2% | 71 min | 0.82% | C+ |
| ATL to LAS · Las Vegas | 720 | 77.0% | 53 min | 0.28% | B+ |
| ATL to PHX · Phoenix | 661 | 72.3% | 50 min | 0.30% | C+ |
| ATL to MSY · New Orleans | 370 | 78.3% | 53 min | 0.27% | B+ |
| ATL to MCI · Kansas City | 365 | 74.4% | 55 min | 0.27% | C+ |
| ATL to IND · Indianapolisthin sample | 336 | 78.4% | 51 min | 0.60% | B+ |
| ATL to CMH · Columbusthin sample | 332 | 78.2% | 48 min | 0.60% | B+ |
| ATL to SAT · San Antoniothin sample | 329 | 82.6% | 49 min | 0.30% | B+ |
| ATL to PIT · Pittsburghthin sample | 311 | 81.6% | 55 min | 0.32% | B+ |
| ATL to RDU · Raleighthin sample | 277 | 82.8% | 68 min | 1.08% | 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 38 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am2,600 flights93.4%
- 8am–11am2,395 flights87.3%
- 11am–2pm3,680 flights84.5%
- 2pm–5pm4,240 flights74.4%
- 5pm–8pm4,015 flights61.5%
- 8pm–5am1,177 flights55.0%
Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 55.0% on time, against 93.4% 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
June is the worst month at 66.1% on time, 22 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.
Delay causes
What holds this operation up
- 48%Late-arriving aircraft
- 26%Carrier
- 21%National Airspace System
- 4%Extreme weather
- 1%Security
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 250,000 reported delay minutes here, that single category outweighs weather by 11 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 1.17% against a national 1.80%, which is ordinary. Diversions add another 0.31%.
7.5% 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.
18,107 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 June 66.1%, a swing of 22 points. If the dates move at all, move them out of June before you think about anything else.
Common questions
Southwest Airlines at ATL
How often is Southwest Airlines at ATL delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.2% of the 18,107 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 ATL?
United Airlines leads at 80.3% on time across 7,431 flights. Frontier Airlines is at the other end on 63.2%, a gap of 17 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 93.4% on time. The 8pm–5am window is the weakest at 55.0%, 38 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 June delays on Southwest Airlines at ATL?
June is the weakest month at 66.1% on time, compared with 88.4% in January. Across the year that is 22 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.