Carrier route record
WNMDW→PHX
Southwest Airlines · Chicago to Phoenix
- Flights
- 2,670
- 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 MDW to PHX sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 2,670 flights, with a median arrival 2 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Southwest on MDW to PHX from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
75.0%
Arrivals under 15 minutes late, of 2,623 completed flights
Avg delay
55 min
Across delayed arrivals only, not all flights
Cancelled
1.50%
National rate is 1.81%
Whole route
75.0%
Every carrier on MDW to PHX, 2,797 flights
These figures cover 2,670 flights between July 2025 and June 2026. The median arrival is 2 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.
Carrier by carrier
Southwest against every carrier on MDW to PHX
Southwest flew 2,670 of the 2,797 flights on MDW to PHX, most of the route. Its 75.0% on time is about level with the route as a whole at 75.0%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Frontier at 75.2% to Southwest at 75.0%. 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 127 | 75.2% | 135 min | 1.57% | B |
| Southwest Airlines (this page) | 2,670 | 75.0% | 55 min | 1.50% | B |
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 29 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–8am544 flights89.1%
- 8am–11am499 flights86.3%
- 11am–2pm377 flights78.3%
- 2pm–5pm445 flights69.1%
- 5pm–8pm463 flights60.0%
- 8pm–5am342 flights59.9%
Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 59.9% on time, against 89.1% 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 544 flights scheduled in it.
Across the year
Southwest on MDW to PHX through the year
June is the worst month at 58.5% on time, 32 points below September, the best at 90.1%. 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. March was the busiest month here, with 258 flights.
Across the week, Saturday is the strongest day at 81.6% on time and Sunday the weakest at 69.3%. 12 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 36,000 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.
- 44%Late-arriving aircraft
- 36%Carrier
- 15%National Airspace System
- 4%Extreme weather
- 1%Security
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 36,000 reported delay minutes here, that single category outweighs weather by 10 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 36,255 reported delay minutes.
The largest share of delay minutes, 36%, 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 13,000 of the 36,000 delay minutes reported here.
Cancellations sit at 1.50% against a national 1.81%, which is ordinary. Diversions add another 0.26%.
Connections and stage length
What a delay here costs
7.1% 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 about an hour, 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 73.4% on time across 2,676 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 2,670 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 MDW to PHX
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 90.1% on time and June 58.5%, a swing of 32 points. If the dates move at all, move them out of June before you think about anything else. 2,623 completed flights over 12 months sit behind that.
Related
Where to go next
- MDW to PHX, every carrier
- Southwest on PHX to MDW, the return leg
- Frontier Airlines on MDW to PHX75.2%
- Southwest Airlines network-wide record
- Chicago Midway International (MDW) delay statistics
- Phoenix Sky Harbor International (PHX) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.