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DelayAtlas

Carrier route record

WNPITLAS

Southwest Airlines · Pittsburgh to Las Vegas

Flights
655
Period
July 2025 to June 2026
Share of route
86%
Carriers
2
B+GRADE

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

Southwest on PIT to LAS lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That is a workable record, not a spotless one. That rests on 655 flights, with a median arrival 5 minutes early.

Set against the rest of the country, Southwest's PIT to LAS record is 5 points better than the US average of 77.6%. That gap is worth roughly 51 fewer late arrivals for every thousand flights.

Key figures

On time

82.7%

Arrivals under 15 minutes late, of 652 completed flights

Avg delay

51 min

Across delayed arrivals only, not all flights

Cancelled

0.46%

National rate is 1.81%

Whole route

82.5%

Every carrier on PIT to LAS, 758 flights

These figures cover 655 flights between July 2025 and June 2026. The median arrival is 5 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 PIT to LAS

Southwest flew 655 of the 758 flights on PIT to LAS, most of the route. Its 82.7% on time is about level with the route as a whole at 82.5%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Southwest at 82.7% to Spirit at 81.4%. 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 PIT to LAS
AirlineFlightsOn timeAvg delayCancelledGrade
Southwest Airlines (this page)65582.7%51 min0.46%B+
Spirit Airlinesthin sample10381.4%58 min0.00%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 38 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–8am301 flights94.7%
  • 8am–11am31 flights100.0%
  • 11am–2pm44 flights84.1%
  • 2pm–5pm88 flights79.5%
  • 5pm–8pm186 flights62.5%
  • 8pm–5am5 flights

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 62.5% on time, against 100.0% for the 8am–11am 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 301 flights scheduled in it.

Across the year

Southwest on PIT to LAS through the year

On-time rate by calendar month83J86F79M87A85M78J80J85A80S82O87N78D
Darker means more delays. Figures are on-time percentages.April best, June worst

June is the worst month at 78.0% on time, 9 points below April, the best at 87.3%. 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. May was the busiest month here, with 66 flights.

Across the week, Wednesday is the strongest day at 89.2% on time and Sunday the weakest at 74.5%. 15 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week80.9Mon88.8Tue89.2Wed78.9Thu79.8Fri88.5Sat74.5Sun
Monday: 80.9 percent on time. Tuesday: 88.8 percent on time. Wednesday: 89.2 percent on time. Thursday: 78.9 percent on time. Friday: 79.8 percent on time. Saturday: 88.5 percent on time. Sunday: 74.5 percent on time

Delay causes

Why Southwest runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 56% of the 5,772 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
    56%
  • Carrier
    22%
  • National Airspace System
    21%
  • Extreme weather
    1%

56% 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 5,772 reported delay minutes here, that single category outweighs weather by 56 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 5,772 reported delay minutes.

The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 100.0% on time here.

Cancellations are rare at 0.46%, 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 4.1% 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.

At 1,910 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The return leg is a different operation and performs like one: it runs 74.5% on time across 654 flights, 8 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 8 points of difference.

One caution: this is a thin sample. 655 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 PIT to LAS

Put together: treat all of this as provisional. 655 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 82.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 652 completed flights over 12 months sit behind that.

Related

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.