Carrier route record
F9MDW→PHX
Frontier Airlines · Chicago to Phoenix
- Flights
- 127
- Period
- July 2025 to June 2026
- Share of route
- 5%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.
Frontier 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, 2 points worse than the national rate of 77.6%. The late ones land about 2.2 hours behind schedule. That rests on 127 flights, with a median arrival 5 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Frontier 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
75.2%
Arrivals under 15 minutes late, of 125 completed flights
Avg delay
135 min
Across delayed arrivals only, not all flights
Cancelled
1.57%
National rate is 1.81%
Whole route
75.0%
Every carrier on MDW to PHX, 2,797 flights
These figures cover 127 flights between July 2025 and June 2026. Beyond the headline rate, 8.8% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Frontier against every carrier on MDW to PHX
Frontier flew 127 of the 2,797 flights on MDW to PHX, about 5% of it. Its 75.2% on time is about level with the route as a whole at 75.0%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Frontier at 75.2% to Southwest at 75.0%.
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 Airlines (this page)thin sample | 127 | 75.2% | 135 min | 1.57% | B |
| Southwest Airlines | 2,670 | 75.0% | 55 min | 1.50% | B |
Departure window
When Frontier runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 127 flights.
There are not enough flights in each departure window to split Frontier's MDW to PHX record by time of day without the percentages moving on noise. The headline rate of 75.2% is the reliable figure here.
Across the year
Frontier on MDW to PHX through the year
- Jul–Sep 202526 flights—
- Oct–Dec 202538 flights70.3%
- Jan–Mar 202651 flights80.0%
- Apr–Jun 202612 flights—
Scale runs 60% to 85%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 75.2% on time across 127 flights.
Split by quarter, Frontier on MDW to PHX logged 26 flights in Jul–Sep 2025, 38 flights in Oct–Dec 2025, 51 flights in Jan–Mar 2026 and 12 flights in Apr–Jun 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 75.2% annual figure is the one to use.
Delay causes
Why Frontier runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 4,177 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.
- 49%Late-arriving aircraft
- 42%Carrier
- 8%National Airspace System
- 1%Extreme weather
49% 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 4,177 reported delay minutes here, that single category outweighs weather by 49 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 4,177 reported delay minutes.
The largest share of delay minutes, 42%, 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 1,760 of the 4,177 delay minutes reported here.
Cancellations sit at 1.57% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
8.8% 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 2.2 hours, 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 is a different operation and performs like one: it runs 66.4% on time across 127 flights, 9 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 9 points of difference.
One caution: this is a thin sample. 127 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 Frontier on MDW to PHX
Put together: treat all of this as provisional. 127 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 75.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 125 completed flights over 12 months sit behind that.
Related
Where to go next
- MDW to PHX, every carrier
- Frontier on PHX to MDW, the return leg
- Southwest Airlines on MDW to PHX75.0%
- Frontier 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
- Connecting flights: how much buffer the data says you need
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.