Atlanta, GA · departure reliability
ATL
Hartsfield-Jackson Atlanta International
- Departures
- 317,109
- Period
- June 2025 to May 2026
- Carriers
- 12
- US rank
- #3 by volume
Atlanta
Hartsfield-Jackson Atlanta International lands a B, level with the national rate of 77.4%. Roughly 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 317,109 flights, of which United Airlines flew 7,431 at 80.3% on time.
United Airlines is the most reliable of the twelve carriers covered here at 80.3% on time across 7,431 flights.
Key figures
On time
77.1%
Departures arriving under 15 minutes late at their destination
Avg delay
66 min
Across delayed flights only
Cancelled
1.83%
National rate is 1.80%
Best carrier
United
80.3% on time here
These figures cover 317,000 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.
Carrier by carrier
Which airlines run best out of ATL
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 |
|---|---|---|---|---|---|
| Delta Air Lines | 241,168 | 78.4% | 60 min | 1.72% | B |
| Frontier Airlines | 19,091 | 63.2% | 83 min | 2.33% | D |
| Southwest Airlines | 18,107 | 76.8% | 60 min | 1.17% | B |
| United Airlines | 7,431 | 80.3% | 83 min | 1.44% | B |
| SkyWest Airlines | 7,416 | 73.7% | 108 min | 2.17% | C |
| American Airlines | 6,851 | 75.9% | 107 min | 2.07% | B |
| Spirit Airlines | 6,049 | 70.5% | 75 min | 2.89% | C |
| PSA Airlines | 3,194 | 78.8% | 108 min | 4.82% | B− |
| Republic Airways | 2,717 | 77.0% | 77 min | 4.05% | B− |
| JetBlue Airways | 2,469 | 70.5% | 92 min | 3.52% | C− |
| Alaska Airlines | 1,463 | 75.4% | 57 min | 0.75% | B+ |
| Envoy Air | 1,153 | 72.7% | 69 min | 3.12% | C− |
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
Busiest routes out of ATL
Route-level records vary far more than the airport average. These are the 25 busiest departures from ATL, each with its own on-time rate against the airport-wide 77.1%.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| ATL to LGA · New York | 8,278 | 72.5% | 76 min | 3.48% | C− |
| ATL to MCO · Orlando | 8,229 | 68.9% | 72 min | 1.39% | C |
| ATL to FLL · Fort Lauderdale | 7,174 | 68.9% | 65 min | 2.16% | C |
| ATL to DCA · Washington | 6,817 | 69.1% | 71 min | 3.36% | C− |
| ATL to DFW · Dallas-Fort Worth | 6,735 | 73.4% | 80 min | 2.72% | C |
| ATL to ORD · Chicago | 6,390 | 70.5% | 81 min | 2.21% | C |
| ATL to EWR · Newark | 6,263 | 71.9% | 74 min | 3.42% | C− |
| ATL to MIA · Miami | 6,245 | 69.7% | 71 min | 1.52% | C |
| ATL to TPA · Tampa | 6,139 | 71.4% | 64 min | 1.27% | C |
| ATL to PHL · Philadelphia | 5,683 | 72.9% | 74 min | 2.96% | C |
| ATL to DEN · Denver | 5,582 | 76.0% | 62 min | 1.09% | B |
| ATL to BWI · Baltimore | 5,430 | 73.9% | 66 min | 2.23% | C |
| ATL to LAX · Los Angeles | 5,097 | 77.5% | 65 min | 1.00% | B |
| ATL to DTW · Detroit | 4,921 | 76.7% | 64 min | 0.87% | B+ |
| ATL to IAH · Houston | 4,908 | 75.4% | 71 min | 2.00% | B |
| ATL to BOS · Boston | 4,904 | 73.6% | 64 min | 1.96% | C |
| ATL to LAS · Las Vegas | 4,843 | 74.9% | 60 min | 0.95% | C+ |
| ATL to RDU · Raleigh | 4,613 | 79.3% | 60 min | 1.50% | B |
| ATL to AUS · Austin | 4,566 | 78.4% | 58 min | 1.51% | B |
| ATL to CLT · Charlotte | 4,461 | 79.5% | 72 min | 1.97% | B |
| ATL to JFK · New York | 4,284 | 73.8% | 85 min | 2.57% | C |
| ATL to BNA · Nashville | 4,226 | 80.1% | 56 min | 1.77% | B |
| ATL to MSY · New Orleans | 4,094 | 79.8% | 60 min | 1.56% | B |
| ATL to JAX · Jacksonville | 3,994 | 73.6% | 59 min | 1.53% | C |
| ATL to IAD · Washington | 3,949 | 75.4% | 82 min | 2.23% | B |
Departure window
The best time of day to leave ATL
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am21,169 flights88.1%
- 8am–11am66,473 flights85.1%
- 11am–2pm50,559 flights82.0%
- 2pm–5pm61,218 flights74.2%
- 5pm–8pm49,894 flights68.7%
- 8pm–5am67,796 flights70.8%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 88.1% of the time, against 68.7% for the evening window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on.
Across the year
When ATL runs late
ATL's year swings by 22 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 64.4% on time, 22 points below September, the best at 86.5%. 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.
Across the week, Wednesday is the strongest day at 82.6% on time and Sunday the weakest at 72.3%. 10 points is a smaller lever than departure hour, but it is free.
Delay causes
Why ATL gets delayed
One category carries most of the weight here. Carrier accounts for 43% of the 4.70 million 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.
- 43%Carrier
- 29%Late-arriving aircraft
- 21%National Airspace System
- 6%Extreme weather
- 0%Security
The largest share of delay minutes, 43%, 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 2.04 million of the 4.70 million delay minutes reported here.
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 88.1% on time here.
Cancellations sit at 1.83% against a national 1.80%, which is ordinary. Diversions add another 0.26%.
7.9% 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.
317,109 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.
What to do with this
Flying out of ATL
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 86.5% on time and June 64.4%, a swing of 22 points. If the dates move at all, move them out of June before you think about anything else.
Common questions
ATL delay questions
How often is Atlanta (ATL) delayed?
Roughly 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 22.9% of the 317,109 flights in this analysis, against 22.6% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on Atlanta (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 Atlanta (ATL)?
The 5am–8am departure window is the strongest at 88.1% on time. The 5pm–8pm window is the weakest at 68.7%, 19 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 Atlanta (ATL)?
June is the weakest month at 64.4% on time, compared with 86.5% in September. 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
- ATL to LGA — New York72.5%
- ATL to MCO — Orlando68.9%
- ATL to FLL — Fort Lauderdale68.9%
- ATL to DCA — Washington69.1%
- ATL to DFW — Dallas-Fort Worth73.4%
- ATL to ORD — Chicago70.5%
- Delta Air Lines on-time record78.4%
- Frontier Airlines on-time record63.2%
- Southwest Airlines on-time record76.8%
- United Airlines on-time record80.3%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.