Carrier route record

WNATL→PIT

Southwest Airlines · Atlanta to Pittsburgh

Flights: 302
Period: July 2025 to June 2026
Share of route: 11%
Carriers: 2

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

Southwest on ATL to PIT lands a B+, 4 points better than the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That is a workable record, not a spotless one. That rests on 302 flights, with a median arrival 4 minutes early.

Set against the rest of the country, Southwest's ATL to PIT record is 4 points better than the US average of 77.6%. That gap is worth roughly 41 fewer late arrivals for every thousand flights.

On time

81.7%

Arrivals under 15 minutes late, of 301 completed flights

Avg delay

55 min

Across delayed arrivals only, not all flights

Cancelled

0.33%

National rate is 1.81%

Whole route

84.5%

Every carrier on ATL to PIT, 2,777 flights

These figures cover 302 flights between July 2025 and June 2026. The median arrival is 4 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 ATL to PIT

Southwest flew 302 of the 2,777 flights on ATL to PIT, about 11% of it. Its 81.7% on time is 3 points worse than the route as a whole, which runs 84.5%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Delta at 84.9% to Southwest at 81.7%.

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 ATL to PIT
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	2,475	84.9%	55 min	2.22%	B
Southwest Airlines (this page)thin sample	302	81.7%	55 min	0.33%	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 15 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–8am—
8am–11am4 flights—
11am–2pm84 flights91.7%
2pm–5pm206 flights77.1%
5pm–8pm8 flights—
8pm–5am—

Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.

The best window here is not the first bank but the 11am–2pm slot at 91.7% on time, ahead of 2pm–5pm at 77.1%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 2pm–5pm window is the busiest, with 206 flights scheduled in it.

Across the year

Southwest on ATL to PIT through the year

Jul–Sep 202579 flights84.8%
Oct–Dec 202587 flights86.2%
Jan–Mar 202683 flights82.9%
Apr–Jun 202653 flights67.9%

Scale runs 60% to 90%. 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 81.7% on time across 302 flights.

Southwest on ATL to PIT did not run the same all year. Its best quarter was Oct–Dec 2025 at 86.2% on time and its weakest Apr–Jun 2026 at 67.9%, a swing of 18 points on roughly 76 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Wednesday is the strongest day at 94.4% on time and Sunday the weakest at 72.5%. 22 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 55% of the 3,019 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
55%
Carrier
33%
National Airspace System
11%
Extreme weather
1%

55% 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 3,019 reported delay minutes here, that single category outweighs weather by 55 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 3,019 reported delay minutes.

Cancellations are rare at 0.33%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 4.0% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 526 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 86.7% on time across 302 flights, 5 points above 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 5 points of difference.

One caution: this is a thin sample. 302 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 ATL to PIT

Put together: treat all of this as provisional. 302 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 81.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 301 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