Carrier route record
WNDEN→BWI
Southwest Airlines · Denver to Baltimore
- Flights
- 1,917
- Period
- September 2025 to August 2026
- Share of route
- 69%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on DEN to BWI sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.3%. The late ones land roughly 50 minutes behind schedule. That rests on 1,917 flights, with a median arrival 3 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate Southwest on DEN to BWI from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
74.9%
Arrivals under 15 minutes late, of 1,881 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
1.15%
National rate is 1.89%
Whole route
77.3%
Every carrier on DEN to BWI, 2,781 flights
These figures cover 1,917 flights between September 2025 and August 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
Southwest against every carrier on DEN to BWI
Southwest flew 1,917 of the 2,781 flights on DEN to BWI, most of the route. Its 74.9% on time is 2 points worse than the route as a whole, which runs 77.3%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from Frontier at 92.0% to Southwest at 74.9%. 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 25 | 92.0% | 82 min | 0.00% | A+ |
| United Airlines | 839 | 82.2% | 51 min | 0.60% | B+ |
| Southwest Airlines (this page) | 1,917 | 74.9% | 51 min | 1.15% | C |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
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 52 points, against half a point between the best and worst carrier.
- 5am–8am461 flights95.8%
- 8am–11am250 flights85.9%
- 11am–2pm236 flights70.2%
- 2pm–5pm352 flights66.0%
- 5pm–8pm320 flights43.4%
- 8pm–5am298 flights80.9%
Scale runs 35% to 100%.
The 5pm–8pm window is where this operation falls apart: 43.4% on time, against 95.8% 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 5am–8am window is the busiest, with 461 flights scheduled in it.
Across the year
Southwest on DEN to BWI through the year
June is the worst month at 62.4% on time, 23 points below January, the best at 85.0%. 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. July was the busiest month here, with 203 flights.
Across the week, Wednesday is the strongest day at 79.0% on time and Thursday the weakest at 70.1%, a spread of 9 points.
Arrival by arrival
How late Southwest on DEN to BWI runs when it is late
The 472 late arrivals split 197 under half an hour, 149 between 30 and 60 minutes, and 126 an hour or more.
- 15+ min early392 flights20.8%
- Within 15 min1,017 flights54.1%
- 15–29 min late197 flights10.5%
- 30–59 min late149 flights7.9%
- 1–2 hours late90 flights4.8%
- 2+ hours late36 flights1.9%
Scale runs 0% to 100%.
Share of 1,881 completed flights by arrival against schedule.
A late pushback is often recovered here: of 620 departures that left 15 minutes late or more, 198 still arrived on time. 50 flights left on time and still arrived late.
The worst days
Worst days for Southwest on DEN to BWI
The latest arrival of the period was on 3 August 2026, 6 hours 27 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. Three of the five worst days fell in August 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 3 August 2026 | 6 hours 27 minutes | Late-arriving aircraft |
| 31 August 2026 | 4 hours 42 minutes | Carrier |
| 3 August 2026 | 4 hours 20 minutes | Carrier |
| 13 March 2026 | 4 hours 9 minutes | National Airspace System |
| 10 July 2026 | 4 hours 1 minute | Late-arriving aircraft |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 52% of the 24,000 delay minutes carriers reported here, and the remaining four split what is left.
- 52%Late-arriving aircraft
- 33%Carrier
- 14%National Airspace System
- 1%Extreme weather
52% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 24,000 reported delay minutes here, that single category outweighs weather by 52 to one. The split is drawn from 24,151 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 95.8% on time here.
Cancellations sit at 1.15% against a national 1.89%, which is ordinary. Diversions add another 0.73%.
Connections and stage length
What a delay here costs
6.7% 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 roughly 50 minutes, which a normal layover absorbs.
The 1,491 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.
The return leg runs 72.2% on time across 1,919 flights, within 3 points 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 1,917 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 DEN to BWI
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 85.0% on time and June 62.4%, a swing of 23 points. If the dates move at all, move them out of June before you think about anything else. 1,881 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to BWI, every carrier
- Southwest on BWI to DEN, the return leg
- United Airlines on DEN to BWI82.2%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.