Carrier route record

WNDTW→MDW

Southwest Airlines · Detroit to Chicago

Flights: 1,047
Period: September 2025 to August 2026
Share of route: 88%
Carriers: 2

Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.

Southwest on DTW to MDW sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.3%. The late ones land roughly 50 minutes behind schedule. That rests on 1,047 flights, with a median arrival 1 minute late.

The national on-time rate over the same period is 77.3%, so Southwest on DTW to MDW runs 5 points behind the country as a whole. Across a thousand flights that is about 49 extra late arrivals.

On time

72.4%

Arrivals under 15 minutes late, of 1,030 completed flights

Avg delay

51 min

Across delayed arrivals only, not all flights

Cancelled

1.24%

National rate is 1.89%

Whole route

73.9%

Every carrier on DTW to MDW, 1,184 flights

These figures cover 1,047 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

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Carrier by carrier

Southwest against every carrier on DTW to MDW

Southwest flew 1,047 of the 1,184 flights on DTW to MDW, most of the route. Its 72.4% on time is 2 points worse than the route as a whole, which runs 73.9%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from SkyWest at 84.7% to Southwest at 72.4%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on DTW to MDW
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlinesthin sample	137	84.7%	49 min	0.00%	B+
Southwest Airlines (this page)	1,047	72.4%	51 min	1.24%	C

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Departure window

When Southwest runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 27 points, against half a point between the best and worst carrier.

5am–8am187 flights83.0%
8am–11am177 flights77.5%
11am–2pm277 flights76.2%
2pm–5pm58 flights80.7%
5pm–8pm189 flights63.1%
8pm–5am159 flights55.8%

Scale runs 45% to 90%.

The 8pm–5am window is where this operation falls apart: 55.8% on time, against 83.0% 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. The 11am–2pm window is the busiest, with 277 flights scheduled in it.

Across the year

Southwest on DTW to MDW through the year

Darker means more delays. Figures are on-time percentages.October best, June worst

June is the worst month at 55.3% on time, 32 points below October, the best at 87.1%. 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. October was the busiest month here, with 93 flights.

Across the week, Friday is the strongest day at 77.7% on time and Monday the weakest at 69.2%, a spread of 9 points.

Arrival by arrival

How late Southwest on DTW to MDW runs when it is late

The 284 late arrivals split 126 under half an hour, 99 between 30 and 60 minutes, and 59 an hour or more.

15+ min early144 flights14.0%
Within 15 min602 flights58.4%
15–29 min late126 flights12.2%
30–59 min late99 flights9.6%
1–2 hours late36 flights3.5%
2+ hours late23 flights2.2%

Scale runs 0% to 100%.

Share of 1,030 completed flights by arrival against schedule.

74 of 298 late departures made up the time and arrived on time, 25% of them. In the other direction, 60 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at MDW.

The worst days

Worst days for Southwest on DTW to MDW

The latest arrival of the period was on 14 June 2026, 8 hours 25 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).

The latest arrivals of Southwest on DTW to MDW in the period
Date	Arrived late by	Largest filed cause
14 June 2026	8 hours 25 minutes	Late-arriving aircraft
27 July 2026	6 hours 3 minutes	National Airspace System
7 October 2025	5 hours 42 minutes	Carrier
17 January 2026	5 hours 27 minutes	Carrier
27 September 2025	5 hours 3 minutes	Carrier

Delay causes

Why Southwest runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 14,000 reported delay minutes.

Late-arriving aircraft
37%
National Airspace System
35%
Carrier
26%
Extreme weather
1%
Security
0%

37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 14,000 reported delay minutes here, that single category outweighs weather by 31 to one. The split is drawn from 14,255 reported delay minutes.

35% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 5,004 minutes out of 14,000, against a national NAS share of 21%.

Cancellations sit at 1.24% against a national 1.89%, which is ordinary. Diversions add another 0.38%.

Connections and stage length

What a delay here costs

5.7% 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 roughly 50 minutes, which a normal layover absorbs.

At 228 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.

The return leg runs 73.9% on time across 1,046 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

One caution: this is a thin sample. 1,047 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking Southwest on DTW to MDW

Put together: treat all of this as provisional. 1,047 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 72.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,030 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures