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DelayAtlas

Carrier route record

WNLASGEG

Southwest Airlines · Las Vegas to Spokane

Flights
750
Period
July 2025 to June 2026
Share of route
88%
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 LAS to GEG lands a B+, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about 45 minutes on average. That is a workable record, not a spotless one. That rests on 750 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 LAS to GEG from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

Key figures

On time

76.7%

Arrivals under 15 minutes late, of 746 completed flights

Avg delay

44 min

Across delayed arrivals only, not all flights

Cancelled

0.53%

National rate is 1.81%

Whole route

76.1%

Every carrier on LAS to GEG, 855 flights

These figures cover 750 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 LAS to GEG

Southwest flew 750 of the 855 flights on LAS to GEG, most of the route. Its 76.7% on time is about level with the route as a whole at 76.1%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Southwest at 76.7% to Allegiant at 72.1%. 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 LAS to GEG
AirlineFlightsOn timeAvg delayCancelledGrade
Southwest Airlines (this page)75076.7%44 min0.53%B+
Allegiant Airthin sample10572.1%65 min0.95%C+

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 23 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–8am25 flights
  • 8am–11am256 flights83.9%
  • 11am–2pm87 flights86.2%
  • 2pm–5pm19 flights
  • 5pm–8pm94 flights85.1%
  • 8pm–5am269 flights63.5%

Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 63.5% on time, against 86.2% for the 11am–2pm 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 8pm–5am window is the busiest, with 269 flights scheduled in it.

Across the year

Southwest on LAS to GEG through the year

On-time rate by calendar month92J88F79M82A67M51J71J73A78S82O76N80D
Darker means more delays. Figures are on-time percentages.January best, June worst

June is the worst month at 50.8% on time, 41 points below January, the best at 92.1%. 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 71 flights.

Across the week, Saturday is the strongest day at 86.4% on time and Sunday the weakest at 66.7%. 20 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week76.9Mon75.5Tue84.6Wed74.8Thu71.0Fri86.4Sat66.7Sun
Monday: 76.9 percent on time. Tuesday: 75.5 percent on time. Wednesday: 84.6 percent on time. Thursday: 74.8 percent on time. Friday: 71.0 percent on time. Saturday: 86.4 percent on time. Sunday: 66.7 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 7,692 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
    37%
  • National Airspace System
    7%

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 7,692 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 7,692 reported delay minutes.

The largest share of delay minutes, 37%, 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 2,855 of the 7,692 delay minutes reported here.

Cancellations are rare at 0.53%, 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

5.6% 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 45 minutes, which a normal layover absorbs.

The 806 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 86.5% on time across 750 flights, 10 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 10 points of difference.

One caution: this is a thin sample. 750 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 LAS to GEG

Put together: treat all of this as provisional. 750 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 76.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 746 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.