Route Reliability

Route reliability

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

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

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

Atlanta, GAChicago, IL

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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

ATL to MDW

Atlanta, GA to Chicago, IL

On time
73.2%vs 75.6% U.S. average Worse than average
Cancelled
2.0%vs 1.9% U.S. average About average
60+ min late
8.2%vs 8.1% U.S. average About average
Scheduled flights
3,537in 12 months3 airlines
Most reliable airline
Delta Air Lines79.5% on time · 1,359 flights

On time less often than 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 ATL to MDW, 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 79.5% 2.4% 5.3% 56 min 0.5% 1,359
2. Southwest Airlines 71.8% 1.6% 7.7% 62 min 0.9% 1,538
3. Frontier Airlines 62.8% 2.5% 15.3% 89 min 0.6% 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 Atlanta (ATL) to Chicago (MDW): 79.5% of its 1,359 scheduled flights arrived within 15 minutes of schedule, compared with 62.8% 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%.
  • 8.2% of flights, about 1 in 12, arrived an hour or more late. When a flight was late (15+ minutes), the average arrival delay was 67 min.
  • Overall, 73.2% of flights on this route arrived on time, 2.4 points lower than the U.S. average of 75.6%.
  • Over the last 3 years, September was the most reliable month on this route (85.3% on time) and July the least reliable (64.9%).
  • Cancellations peaked in January, when 4.6% of flights were cancelled.
  • Flights scheduled to depart 6 am to 7 am were the most punctual (92.9% on time); flights scheduled to depart 7 pm to 8 pm were the least (49.1%).
  • In the other direction, Chicago (MDW) to Atlanta (ATL), 76.8% of flights were on time and 2.0% were cancelled. Compare airlines MDW to ATL.

Best and worst months to fly ATL to MDW

Jan 75.7%
Feb 83.2%
Mar 78.0%
Apr 79.9%
May 69.1%
Jun 71.5%
Jul 64.9%
Aug 74.6%
Sep 85.3%
Oct 83.6%
Nov 81.2%
Dec 77.9%
Share of scheduled flights on time 12-month average 73.2%
All airlines combined, by calendar month, September 2023 to August 2026 (3 years pooled). Scale starts at zero.
Show as table
PeriodOn timeFlights
January 75.7% 824
February 83.2% 750
March 78.0% 900
April 79.9% 925
May 69.1% 957
June 71.5% 955
July 64.9% 986
August 74.6% 969
September 85.3% 932
October 83.6% 1,001
November 81.2% 926
December 77.9% 893
Best and worst calendar month by airline, September 2023 to August 2026.
AirlineBest monthWorst month
Delta Air Lines September (88.1%) July (67.9%)
Southwest Airlines September (88.4%) May (63.4%)
Frontier Airlines February (72.3%) June (49.3%)

Month by month, last 12 months

Sep 90.4%
Oct 79.6%
Nov 76.4%
Dec 69.7%
Jan 79.5%
Feb 77.4%
Mar 67.8%
Apr 82.1%
May 64.0%
Jun 68.2%
Jul 62.5%
Aug 63.3%
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 90.4% 292
Oct 2025 79.6% 304
Nov 2025 76.4% 288
Dec 2025 69.7% 290
Jan 2026 79.5% 278
Feb 2026 77.4% 261
Mar 2026 67.8% 289
Apr 2026 82.1% 291
May 2026 64.0% 297
Jun 2026 68.2% 308
Jul 2026 62.5% 323
Aug 2026 63.3% 316

Best and worst departure times

6a 92.9%
7a 79.3%
8a 80.4%
9a 79.8%
10a 77.6%
11a 82.0%
12p 82.2%
1p 84.6%
2p 65.4%
3p 77.2%
4p 70.4%
5p 65.7%
6p 65.5%
7p 49.1%
8p 57.5%
9p 61.8%
10p 77.1%
Share of scheduled flights on time
By scheduled local departure hour at ATL, September 2025 to August 2026. Hours with no scheduled flights are omitted. Scale starts at zero.
Show as table
PeriodOn timeFlights
Departing 6 am to 7 am 92.9% 156
Departing 7 am to 8 am 79.3% 82
Departing 8 am to 9 am 80.4% 377
Departing 9 am to 10 am 79.8% 168
Departing 10 am to 11 am 77.6% 219
Departing 11 am to noon 82.0% 400
Departing noon to 1 pm 82.2% 135
Departing 1 pm to 2 pm 84.6% 78
Departing 2 pm to 3 pm 65.4% 104
Departing 3 pm to 4 pm 77.2% 347
Departing 4 pm to 5 pm 70.4% 206
Departing 5 pm to 6 pm 65.7% 169
Departing 6 pm to 7 pm 65.5% 194
Departing 7 pm to 8 pm 49.1% 163
Departing 8 pm to 9 pm 57.5% 134
Departing 9 pm to 10 pm 61.8% 500
Departing 10 pm to 11 pm 77.1% 105
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 Atlanta, GA (ATL) to Chicago, IL (MDW), 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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