Carrier route record

WNPHX→MDW

Southwest Airlines · Phoenix to Chicago

Flights: 2,676
Period: July 2025 to June 2026
Share of route: 95%
Carriers: 2

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

Southwest on PHX to MDW sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land roughly 45 minutes behind schedule. That rests on 2,676 flights, with a median arrival 1 minute late.

The national on-time rate over the same period is 77.6%, so Southwest on PHX to MDW runs 4 points behind the country as a whole. Across a thousand flights that is about 42 extra late arrivals.

On time

73.4%

Arrivals under 15 minutes late, of 2,633 completed flights

Avg delay

47 min

Across delayed arrivals only, not all flights

Cancelled

1.05%

National rate is 1.81%

Whole route

73.1%

Every carrier on PHX to MDW, 2,803 flights

These figures cover 2,676 flights between July 2025 and June 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.

Carrier by carrier

Southwest against every carrier on PHX to MDW

Southwest flew 2,676 of the 2,803 flights on PHX to MDW, most of the route. Its 73.4% on time is about level with the route as a whole at 73.1%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Southwest at 73.4% to Frontier at 66.4%. 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 PHX to MDW
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlines (this page)	2,676	73.4%	47 min	1.05%	C
Frontier Airlinesthin sample	127	66.4%	80 min	1.57%	C

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 30 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am584 flights90.4%
8am–11am498 flights82.4%
11am–2pm408 flights70.2%
2pm–5pm510 flights62.4%
5pm–8pm485 flights60.4%
8pm–5am191 flights66.7%

Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 60.4% on time, against 90.4% 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 5am–8am window is the busiest, with 584 flights scheduled in it.

Across the year

Southwest on PHX to MDW through the year

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

June is the worst month at 61.4% on time, 23 points below September, the best at 84.5%. 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. March was the busiest month here, with 258 flights.

Across the week, Wednesday is the strongest day at 79.0% on time and Monday the weakest at 69.4%. 10 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Southwest runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 44% of the 33,000 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.

Late-arriving aircraft
44%
Carrier
37%
National Airspace System
16%
Extreme weather
3%
Security
0%

44% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 33,000 reported delay minutes here, that single category outweighs weather by 15 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 33,171 reported delay minutes.

The largest share of delay minutes, 37%, 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 12,000 of the 33,000 delay minutes reported here.

Cancellations sit at 1.05% against a national 1.81%, which is ordinary. Diversions add another 0.56%.

Connections and stage length

What a delay here costs

6.5% of arrivals land an hour or more late, close to the national 8.1%. 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 last roughly 45 minutes, which a normal layover absorbs.

The 1,444 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg runs 75.0% on time across 2,670 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.

The sample behind these figures is 2,676 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.

What to do with this

Booking Southwest on PHX to MDW

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 84.5% on time and June 61.4%, a swing of 23 points. If the dates move at all, move them out of June before you think about anything else. 2,633 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures