Route Reliability

Route reliability

Chicago (MDW) to Atlanta (ATL): which airline is most on time?

On-time arrivals, cancellations and long delays for every airline that reported nonstop flights from Chicago, IL (MDW) to Atlanta, GA (ATL), September 2025 to August 2026.

Historical performance Official DOT data through August 2026 · Not live flight status

Chicago, ILAtlanta, GA

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Three-letter airport codes, nonstop U.S. domestic flights. One direction at a time.

Route at a glance · September 2025 to August 2026

MDW to ATL

Chicago, IL to Atlanta, GA

On time
76.8%vs 75.6% U.S. average About average
Cancelled
2.0%vs 1.9% U.S. average About average
60+ min late
6.6%vs 8.1% U.S. average Better than average
Scheduled flights
3,538in 12 months3 airlines
Most reliable airline
Delta Air Lines84.0% on time · 1,359 flights

On time about as often as the U.S. average, with a typical cancellation rate.

Compared with all U.S. flights, September 2025 to August 2026. “About average” means within 1.5 points for on time, 0.3 for cancelled and 1 for 60+ minutes late.

Airlines on this route

Ranked by on-time arrival

Airlines from MDW to ATL, September 2025 to August 2026. Rates are shares of all scheduled flights.
Airline On time Cancelled 60+ min late Avg delay when late Diverted Flights
1. Delta Air Lines Most reliable 84.0% 2.7% 5.4% 95 min 0.7% 1,359
2. Southwest Airlines 74.1% 1.1% 7.4% 57 min 0.3% 1,539
3. Frontier Airlines 67.8% 2.7% 6.9% 52 min 0.2% 640

On time = arrived within 15 minutes of schedule. Avg delay when late = average arrival delay of flights 15+ minutes late. "Most reliable" needs at least 300 flights in 12 months. Tap a heading to sort.

What this means

Delta Air Lines has the strongest record on this route.

  • Delta Air Lines had the best on-time record from Chicago (MDW) to Atlanta (ATL): 84.0% of its 1,359 scheduled flights arrived within 15 minutes of schedule, compared with 67.8% for Frontier Airlines.
  • 2.0% of flights on this route were cancelled (about 1 in 50), about the same as the U.S. average of 1.9%.
  • 6.6% of flights, about 1 in 15, arrived an hour or more late. When a flight was late (15+ minutes), the average arrival delay was 64 min.
  • Overall, 76.8% of flights on this route arrived on time, 1.2 points higher than the U.S. average of 75.6%.
  • Over the last 3 years, October was the most reliable month on this route (87.0% on time) and July the least reliable (66.0%).
  • Cancellations peaked in January, when 5.5% of flights were cancelled.
  • Flights scheduled to depart 9 am to 10 am were the most punctual (89.9% on time); flights scheduled to depart 6 pm to 7 pm were the least (65.7%).
  • In the other direction, Atlanta (ATL) to Chicago (MDW), 73.2% of flights were on time and 2.0% were cancelled. Compare airlines ATL to MDW.

Best and worst months to fly MDW to ATL

Jan 74.4%
Feb 83.5%
Mar 78.6%
Apr 82.2%
May 77.7%
Jun 75.2%
Jul 66.0%
Aug 78.3%
Sep 85.6%
Oct 87.0%
Nov 85.2%
Dec 80.3%
Share of scheduled flights on time 12-month average 76.8%
All airlines combined, by calendar month, September 2023 to August 2026 (3 years pooled). Scale starts at zero.
Show as table
PeriodOn timeFlights
January 74.4% 820
February 83.5% 739
March 78.6% 901
April 82.2% 914
May 77.7% 942
June 75.2% 957
July 66.0% 986
August 78.3% 969
September 85.6% 931
October 87.0% 999
November 85.2% 927
December 80.3% 892
Best and worst calendar month by airline, September 2023 to August 2026.
AirlineBest monthWorst month
Delta Air Lines October (92.3%) July (71.1%)
Southwest Airlines October (86.2%) July (63.7%)
Frontier Airlines October (77.1%) January (54.4%)

Month by month, last 12 months

Sep 87.7%
Oct 87.5%
Nov 78.1%
Dec 75.5%
Jan 78.1%
Feb 79.2%
Mar 72.0%
Apr 83.8%
May 75.2%
Jun 72.7%
Jul 62.5%
Aug 70.9%
Share of scheduled flights on time U.S. average 75.6%
All airlines combined, September 2025 to August 2026. Scale starts at zero.
Show as table
PeriodOn timeFlights
Sep 2025 87.7% 292
Oct 2025 87.5% 304
Nov 2025 78.1% 288
Dec 2025 75.5% 290
Jan 2026 78.1% 279
Feb 2026 79.2% 260
Mar 2026 72.0% 289
Apr 2026 83.8% 291
May 2026 75.2% 298
Jun 2026 72.7% 308
Jul 2026 62.5% 323
Aug 2026 70.9% 316

Best and worst departure times

<6a Insufficient sample
6a 78.3%
7a 88.6%
8a 85.6%
9a 89.9%
10a 85.4%
11a 73.4%
12p 75.6%
1p 75.7%
2p 74.9%
3p 68.2%
4p 67.8%
5p 75.3%
6p 65.7%
7p 61.4%
8p Insufficient sample
9p Insufficient sample
Share of scheduled flights on time
By scheduled local departure hour at MDW, September 2025 to August 2026. Hours with no scheduled flights are omitted. Scale starts at zero.
Show as table
PeriodOn timeFlights
Departing before 6 am Insufficient sample 16
Departing 6 am to 7 am 78.3% 709
Departing 7 am to 8 am 88.6% 167
Departing 8 am to 9 am 85.6% 187
Departing 9 am to 10 am 89.9% 159
Departing 10 am to 11 am 85.4% 309
Departing 11 am to noon 73.4% 199
Departing noon to 1 pm 75.6% 480
Departing 1 pm to 2 pm 75.7% 111
Departing 2 pm to 3 pm 74.9% 199
Departing 3 pm to 4 pm 68.2% 110
Departing 4 pm to 5 pm 67.8% 143
Departing 5 pm to 6 pm 75.3% 328
Departing 6 pm to 7 pm 65.7% 289
Departing 7 pm to 8 pm 61.4% 83
Departing 8 pm to 9 pm Insufficient sample 30
Departing 9 pm to 10 pm Insufficient sample 19
Woman at an airport window watching a plane take off
Photo: Depositphotos (licensed stock, illustrative only). Credits

Sources & data dates

Source
U.S. DOT Bureau of Transportation Statistics, Reporting Carrier On-Time Performance (1987-present)
Period
September 2025 to August 2026 (12 months); month-of-year patterns September 2023 to August 2026
Data through
August 2026
Processed
2026-11-03
Scope
Nonstop scheduled flights from Chicago, IL (MDW) to Atlanta, GA (ATL), one direction. Airlines that report to the DOT only.
Method
Rates use all scheduled flights as the denominator; cancelled and diverted flights count as not on time. Figures based on fewer than 50 scheduled flights are suppressed. Full methodology.

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