Carrier route record

WNLAS→BWI

Southwest Airlines · Las Vegas to Baltimore

Flights: 1,625
Period: July 2025 to June 2026
Share of route: 90%
Carriers: 2

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

Southwest on LAS to BWI lands a B+, about a point 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 45 minutes on average. That is a workable record, not a spotless one. That rests on 1,625 flights, with a median arrival 4 minutes early.

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

On time

78.5%

Arrivals under 15 minutes late, of 1,601 completed flights

Avg delay

46 min

Across delayed arrivals only, not all flights

Cancelled

0.92%

National rate is 1.81%

Whole route

78.5%

Every carrier on LAS to BWI, 1,803 flights

These figures cover 1,625 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 LAS to BWI

Southwest flew 1,625 of the 1,803 flights on LAS to BWI, most of the route. Its 78.5% on time is about level with the route as a whole at 78.5%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from Spirit at 79.0% to Southwest at 78.5%. 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 BWI
Airline	Flights	On time	Avg delay	Cancelled	Grade
Spirit Airlinesthin sample	178	79.0%	93 min	1.12%	B
Southwest Airlines (this page)	1,625	78.5%	46 min	0.92%	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 34 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–8am364 flights93.3%
8am–11am260 flights79.3%
11am–2pm228 flights71.6%
2pm–5pm326 flights59.6%
5pm–8pm82 flights59.3%
8pm–5am365 flights88.2%

Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 59.3% on time, against 93.3% 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 365 flights scheduled in it.

Across the year

Southwest on LAS to BWI through the year

Darker means more delays. Figures are on-time percentages.January best, July worst

July is the worst month at 64.0% on time, 27 points below January, the best at 91.0%. 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. December was the busiest month here, with 149 flights.

Across the week, Saturday is the strongest day at 89.3% on time and Sunday the weakest at 70.8%. 19 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. Carrier accounts for 44% of the 16,000 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.

Carrier
44%
Late-arriving aircraft
42%
National Airspace System
13%
Extreme weather
1%
Security
0%

42% 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 16,000 reported delay minutes here, that single category outweighs weather by 42 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 15,700 reported delay minutes.

The largest share of delay minutes, 44%, 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 6,895 of the 16,000 delay minutes reported here.

Cancellations sit at 0.92% against a national 1.81%, which is ordinary. Diversions add another 0.55%.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 4.7% 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 2,106 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 runs 78.1% on time across 1,630 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 1,625 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking Southwest on LAS to BWI

Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 91.0% on time and July 64.0%, a swing of 27 points. If the dates move at all, move them out of July before you think about anything else. 1,601 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