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DelayAtlas

Carrier route record

WNCLELAS

Southwest Airlines · Cleveland to Las Vegas

Flights
369
Period
July 2025 to June 2026
Share of route
38%
Carriers
4
B+GRADE

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

Southwest on CLE to LAS lands a B+, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 369 flights, with a median arrival 3 minutes early.

The US average over the same twelve months is 77.6%, so there is little to separate Southwest on CLE to LAS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

Key figures

On time

80.3%

Arrivals under 15 minutes late, of 366 completed flights

Avg delay

55 min

Across delayed arrivals only, not all flights

Cancelled

0.54%

National rate is 1.81%

Whole route

77.9%

Every carrier on CLE to LAS, 981 flights

These figures cover 369 flights between July 2025 and June 2026. The median arrival is 3 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 CLE to LAS

Southwest flew 369 of the 981 flights on CLE to LAS, about 38% of it. Its 80.3% on time is 2 points better than the route as a whole, which runs 77.9%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from American at 100.0% to Frontier at 76.3%. Two 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 CLE to LAS
AirlineFlightsOn timeAvg delayCancelledGrade
American Airlinesthin sample2100.0%0.00%A+
Delta Air Linesthin sample1100.0%0.00%A+
Southwest Airlines (this page)36980.3%55 min0.54%B+
Frontier Airlines60976.3%90 min1.31%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 26 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–8am37 flights100.0%
  • 8am–11am4 flights
  • 11am–2pm159 flights81.6%
  • 2pm–5pm123 flights74.6%
  • 5pm–8pm6 flights
  • 8pm–5am40 flights74.4%

Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 100.0% of the time, against 74.4% for the overnight window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 159 flights scheduled in it.

Across the year

Southwest on CLE to LAS through the year

On-time rate by calendar month84JF80MA74M70J82J84A87S87O90N60D
Darker means more delays. Figures are on-time percentages.November best, December worst

December is the weak month at 60.0% on time, against 90.0% in November. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. July was the busiest month here, with 34 flights.

Across the week, Wednesday is the strongest day at 92.3% on time and Monday the weakest at 69.2%. 23 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week69.2Mon82.7Tue92.3Wed80.4Thu88.0Fri78.9Sat71.2Sun
Monday: 69.2 percent on time. Tuesday: 82.7 percent on time. Wednesday: 92.3 percent on time. Thursday: 80.4 percent on time. Friday: 88.0 percent on time. Saturday: 78.9 percent on time. Sunday: 71.2 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 66% of the 3,959 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
    66%
  • National Airspace System
    20%
  • Carrier
    13%
  • Security
    0%

66% 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 3,959 reported delay minutes here, that single category outweighs weather by 66 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 3,959 reported delay minutes.

The practical consequence: the 5am–8am 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 0.54%, 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 4.6% 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 1,824 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 75.9% on time across 369 flights, 4 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 4 points of difference.

One caution: this is a thin sample. 369 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 CLE to LAS

Put together: treat all of this as provisional. 369 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 80.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 366 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.