Carrier performance at one airport
WN→BWI
Southwest Airlines at Baltimore/Washington International Thurgood Marshall
- Departures
- 71,953
- Period
- September 2025 to August 2026
- Routes
- 25
- Rank here
- #7 of 9
Southwest Airlines at Baltimore lands a B, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That rests on 71,953 flights, of which Delta Air Lines flew 5,297 at 85.3% on time.
Measured against the airport rather than the country, Southwest Airlines runs half a point behind the 77.0% weighted average across all carriers at BWI. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
76.5%
70,510 completed departures
Avg delay
55 min
Across delayed flights only
Cancelled
1.80%
At BWI, this carrier only
Rank here
#7
Of 9 carriers clearing the floor at BWI
These figures cover 72,000 flights between September 2025 and August 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.
Against the competition
Every carrier at BWI, ranked
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 85.3% of the time; Frontier Airlines manages 68.1%. Sample sizes sit next to every figure, because a two-point gap across 3,640 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 5,297 | 85.3% | 90 min | 1.98% | A |
| Republic Airways | 1,435 | 81.1% | 88 min | 4.25% | B− |
| American Airlines | 3,473 | 80.5% | 104 min | 2.10% | B |
| United Airlines | 4,172 | 80.1% | 72 min | 0.93% | B+ |
| Spirit Airlines | 2,160 | 78.6% | 74 min | 3.29% | B− |
| Envoy Air | 966 | 76.8% | 82 min | 3.31% | B− |
| Southwest Airlines (this page) | 71,953 | 76.5% | 55 min | 1.80% | B |
| Alaska Airlines | 710 | 69.2% | 52 min | 0.85% | C+ |
| Frontier Airlines | 3,640 | 68.1% | 88 min | 4.04% | C− |
Republic Airways cancels 4.3% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Where Southwest Airlines flies from BWI
Southwest Airlines operates 25 routes out of BWI with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| BWI to MCO · Orlando | 3,614 | 76.8% | 63 min | 2.24% | B |
| BWI to BOS · Boston | 2,415 | 71.1% | 61 min | 2.77% | C |
| BWI to TPA · Tampa | 2,287 | 78.3% | 58 min | 1.84% | B |
| BWI to FLL · Fort Lauderdale | 2,124 | 75.7% | 55 min | 1.69% | B |
| BWI to DEN · Denver | 1,919 | 72.2% | 50 min | 1.82% | C |
| BWI to PVD · Providence | 1,846 | 79.6% | 50 min | 2.28% | B |
| BWI to DAL · Dallas | 1,794 | 75.8% | 53 min | 2.06% | B |
| BWI to MDW · Chicago | 1,768 | 75.1% | 60 min | 2.38% | B |
| BWI to RDU · Raleigh | 1,765 | 80.7% | 60 min | 2.61% | B |
| BWI to BNA · Nashville | 1,754 | 79.0% | 55 min | 1.82% | B |
| BWI to ALB · Albany | 1,740 | 80.4% | 53 min | 1.78% | B |
| BWI to BUF · Buffalo | 1,727 | 75.9% | 52 min | 2.14% | B |
| BWI to BDL · Hartford | 1,723 | 81.2% | 55 min | 2.21% | B |
| BWI to MHT · Manchester | 1,721 | 84.2% | 60 min | 1.39% | B |
| BWI to LAS · Las Vegas | 1,624 | 78.3% | 54 min | 0.99% | B+ |
| BWI to ATL · Atlanta | 1,559 | 76.4% | 54 min | 1.54% | B |
| BWI to ORF · Norfolk | 1,539 | 78.5% | 50 min | 1.62% | B |
| BWI to HOU · Houston | 1,471 | 75.7% | 55 min | 1.43% | B |
| BWI to RSW · Fort Myers | 1,407 | 74.7% | 54 min | 1.99% | C |
| BWI to JAX · Jacksonville | 1,401 | 76.0% | 49 min | 1.64% | B |
| BWI to PWM · Portland | 1,331 | 80.6% | 45 min | 1.65% | B |
| BWI to ISP · Islip | 1,260 | 77.8% | 52 min | 1.90% | B |
| BWI to STL · St. Louis | 1,260 | 81.3% | 56 min | 1.27% | B |
| BWI to AUS · Austin | 1,254 | 77.0% | 50 min | 1.67% | B |
| BWI to SRQ · Sarasota | 1,248 | 80.1% | 57 min | 1.92% | B |
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 27 points, against 17 points between the best and worst carrier.
- 5am–8am6,811 flights91.3%
- 8am–11am17,412 flights87.5%
- 11am–2pm10,244 flights79.7%
- 2pm–5pm12,377 flights72.2%
- 5pm–8pm12,459 flights66.3%
- 8pm–5am12,650 flights64.8%
Scale runs 55% to 95%.
The 8pm–5am window is where this operation falls apart: 64.8% on time, against 91.3% 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 8am–11am window is the busiest, with 17,412 flights scheduled in it.
Across the year
Seasonal pattern
August is the worst month at 68.0% on time, 17 points below September, the best at 85.4%. 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. July was the busiest month here, with 6,466 flights.
Delay causes
What holds this operation up
- 41%Late-arriving aircraft
- 35%Carrier
- 19%National Airspace System
- 5%Extreme weather
- 1%Security
41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 904,000 reported delay minutes here, that single category outweighs weather by 9 to one. The split is drawn from 904,079 reported delay minutes.
Cancellations sit at 1.80% against a national 1.89%, which is ordinary. Diversions add another 0.21%.
6.5% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 55 minutes, which a normal layover absorbs.
71,953 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 85.4% on time and August 68.0%, a swing of 17 points. If the dates move at all, move them out of August before you think about anything else. 70,510 completed flights over 12 months sit behind that.
Common questions
Southwest Airlines at BWI
How often is Southwest Airlines at BWI delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.5% of the 71,953 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 55 minutes on average.
Which airline is most reliable on Southwest Airlines at BWI?
Delta Air Lines leads at 85.3% on time across 5,297 flights. Frontier Airlines is at the other end on 68.1%, a gap of 17 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on Southwest Airlines at BWI?
The 5am–8am departure window is the strongest at 91.3% on time. The 8pm–5am window is the weakest at 64.8%, 27 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are August delays on Southwest Airlines at BWI?
August is the weakest month at 68.0% on time, compared with 85.4% in September. Across the year that is 17 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- Southwest Airlines network-wide record
- Baltimore/Washington International Thurgood Marshall (BWI) all carriers
- BWI to MCO route record76.8%
- BWI to BOS route record71.1%
- BWI to TPA route record78.3%
- BWI to FLL route record75.7%
- Do airlines run better at their own hubs?
- Why the first flight of the morning is statistically safest
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.