Route reliability record
MDW→ATL
Chicago to Atlanta
- Flights
- 3,538
- Period
- September 2025 to August 2026
- Distance
- 591 mi
- Carriers
- 3
This route lands a B, about a point better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 3,538 MDW to ATL flights, of which Delta Air Lines flew 1,359 at 87.0% on time.
Best time to fly MDW to ATL: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 89.2% of the time and Tuesday flights 84.3%, against 78.7% for the route overall.
Delta Air Lines is the most reliable of the three carriers covered here at 87.0% on time across 1,359 flights.
Key figures
On time
78.7%
Arrivals under 15 minutes late, of 3,453 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
2.01%
National rate is 1.89%
Best carrier
Delta
87.0% on time across 1,359 flights
These figures cover 3,538 flights between September 2025 and August 2026. The median arrival is 8 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.
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Carrier by carrier
Which airline is most reliable on MDW to ATL
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 87.0% of the time; Frontier Airlines manages 69.8%. Sample sizes sit next to every figure, because a two-point gap across 640 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,359 | 87.0% | 95 min | 2.72% | A |
| Southwest Airlines | 1,539 | 75.1% | 57 min | 1.10% | B |
| Frontier Airlines | 640 | 69.8% | 52 min | 2.66% | C |
The spread between Delta and Frontier is 17 points, wide enough that it should decide the booking. On a hundred trips that is 17 more arrivals inside the on-time window.
Flight by flight
Flights on MDW to ATL
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Chicago to Atlanta
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 3 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. MDW → ATLChicago to Atlanta | Delta Air Lines | 84.6% | 87.0% | 2.72% | 5am–8am, Wed | DL 1285 06:00 |
| 2. ORD → ATLChicago to Atlanta | Delta Air Lines | 77.9% | 79.8% | 2.40% | 5am–8am, Wed | DL 1264 05:30 |
| 3. ORD → ATLChicago to Atlanta | Envoy Air | 75.9% | 77.6% | 2.19% | 5am–8am, Mon | — |
| 4. MDW → ATLChicago to Atlanta | Southwest Airlines | 74.3% | 75.1% | 1.10% | 5am–8am, Tue | — |
| 5. ORD → ATLChicago to Atlanta | United Airlines | 73.5% | 74.5% | 1.34% | 5am–8am, Tue | UA 356 14:25 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 23 points, against 17 points between the best and worst carrier.
- 5am–8am874 flights82.8%
- 8am–11am608 flights89.2%
- 11am–2pm850 flights77.3%
- 2pm–5pm445 flights72.9%
- 5pm–8pm710 flights70.8%
- 8pm–5am51 flights66.0%
Scale runs 60% to 95%.
Book the morning departure. Flights leaving between 8am–11am arrive on time 89.2% of the time, against 66.0% for the overnight window. That is 23 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 874 flights scheduled in it.
Explore
Filter MDW to ATL by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On MDW to ATL, the best departure window is 8am–11am at 89.2% on time and the worst is 8pm–5am at 66.0%, a wide gap of 23.2 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am82.8%
- 8–11am89.2%
- 11am–2pm77.3%
- 2–5pm72.9%
- 5–8pm70.8%
- 8pm–5am66.0%
best all US flightsScale 60% to 95%.
Across the year
When delays peak on this route
This route'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.
July is the worst month at 66.2% on time, 22 points below October, the best at 87.8%. 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. July was the busiest month here, with 323 flights.
Across the week, Tuesday is the strongest day at 84.3% on time and Sunday the weakest at 73.1%, a spread of 11 points.
Delay causes
Why this route gets delayed
Carrier accounts for 42% of the 47,000 delay minutes carriers reported here, and the remaining four split what is left.
- 42%Carrier
- 32%Late-arriving aircraft
- 22%National Airspace System
- 3%Extreme weather
- 1%Security
The largest share of delay minutes, 42%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 20,000 of the 47,000 delay minutes reported here. The split is drawn from 47,435 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 89.2% on time here.
Cancellations sit at 2.01% against a national 1.89%, which is ordinary. Diversions add another 0.40%.
Connections and stage length
What a delay here actually costs
6.7% 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.
The 591 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.
The return leg is a different operation and performs like one: it runs 75.2% on time across 3,537 flights, 4 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 4 points of difference.
The sample behind these figures is 3,538 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.
Work out the risk of missing a connection in ATL after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. October runs 87.8% on time and July 66.2%, a swing of 22 points. If the dates move at all, move them out of July before you think about anything else. 3,453 completed flights over 12 months sit behind that.
Common questions
MDW to ATL questions
How often is MDW to ATL delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.3% of the 3,538 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on MDW to ATL?
Delta Air Lines leads at 87.0% on time across 1,359 flights. Frontier Airlines is at the other end on 69.8%, 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 MDW to ATL?
The 8am–11am departure window is the strongest at 89.2% on time. The 8pm–5am window is the weakest at 66.0%, 23 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 MDW to ATL?
July is the weakest month at 66.2% on time, compared with 87.8% in October. 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 MDW — the return legseparate record
- Chicago Midway International (MDW) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Delta Air Lines on MDW to ATL87.0%
- Southwest Airlines on MDW to ATL75.1%
- Frontier Airlines on MDW to ATL69.8%
- MDW to PHX, a related route74.7%
- LGA to ATL, a related route75.5%
- MDW to MCO, a related route75.2%
- Delta Air Lines on-time record87.0%
- Southwest Airlines on-time record75.1%
- Frontier Airlines on-time record69.8%
- Same route, different airline: where the carrier you pick matters most
- The best time of day to fly, according to 7.05 million flight records
Direction matters. MDW to ATL and ATL to MDW are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.