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DelayAtlas

Carrier route record

WNBNALAX

Southwest Airlines · Nashville to Los Angeles

Flights
927
Period
July 2025 to June 2026
Share of route
40%
Carriers
4
C+GRADE

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

Southwest on BNA to LAX sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land roughly 45 minutes behind schedule. That rests on 927 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 909 at 85.5% on time.

The national on-time rate over the same period is 77.6%, so Southwest on BNA to LAX runs 7 points behind the country as a whole. Across a thousand flights that is about 69 extra late arrivals.

Key figures

On time

70.7%

Arrivals under 15 minutes late, of 919 completed flights

Avg delay

43 min

Across delayed arrivals only, not all flights

Cancelled

0.65%

National rate is 1.81%

Whole route

77.0%

Every carrier on BNA to LAX, 2,317 flights

These figures cover 927 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

Carrier by carrier

Southwest against every carrier on BNA to LAX

Southwest flew 927 of the 2,317 flights on BNA to LAX, about 40% of it. Its 70.7% on time is 6 points worse than the route as a whole, which runs 77.0%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from Delta at 85.5% to Southwest at 70.7%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 85.5% of the time; American Airlines manages 72.0%. Sample sizes sit next to every figure, because a two-point gap across 413 flights means less than a ten-point one.

On-time performance by carrier on BNA to LAX
AirlineFlightsOn timeAvg delayCancelledGrade
Delta Air Lines90985.5%61 min1.32%A
Spirit Airlinesthin sample6880.6%124 min1.47%B
American Airlines41372.0%95 min0.73%C+
Southwest Airlines (this page)92770.7%43 min0.65%C+

The spread between Delta and American is 14 points, wide enough that it should decide the booking. On a hundred trips that is 14 more arrivals inside the on-time window.

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 46 points, against 14 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am191 flights91.5%
  • 8am–11am147 flights86.2%
  • 11am–2pm31 flights74.2%
  • 2pm–5pm170 flights55.9%
  • 5pm–8pm65 flights45.3%
  • 8pm–5am323 flights64.1%

Scale runs 35% to 95%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 45.3% on time, against 91.5% for the 5am–8am 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 323 flights scheduled in it.

Across the year

Southwest on BNA to LAX through the year

On-time rate by calendar month88J75F91M59A60M44J73J77A77S70O78N68D
Darker means more delays. Figures are on-time percentages.March best, June worst

June is the worst month at 44.4% on time, 46 points below March, the best at 90.7%. 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. June was the busiest month here, with 90 flights.

Across the week, Tuesday is the strongest day at 77.8% on time and Sunday the weakest at 61.3%. 17 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week65.9Mon77.8Tue74.2Wed74.0Thu70.8Fri73.3Sat61.3Sun
Monday: 65.9 percent on time. Tuesday: 77.8 percent on time. Wednesday: 74.2 percent on time. Thursday: 74.0 percent on time. Friday: 70.8 percent on time. Saturday: 73.3 percent on time. Sunday: 61.3 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 52% of the 12,000 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
    52%
  • Carrier
    35%
  • National Airspace System
    11%
  • Extreme weather
    1%
  • Security
    0%

52% 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 12,000 reported delay minutes here, that single category outweighs weather by 43 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 11,684 reported delay minutes.

The largest share of delay minutes, 35%, 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 4,145 of the 12,000 delay minutes reported here.

Cancellations are rare at 0.65%, 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

6.0% 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 roughly 45 minutes, which a normal layover absorbs.

At 1,798 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 79.8% on time across 928 flights, 9 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 9 points of difference.

One caution: this is a thin sample. 927 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 BNA to LAX

Put together: treat all of this as provisional. 927 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 70.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 919 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.