Route reliability record
DEN→BWI
Denver to Baltimore
- Flights
- 2,781
- Period
- September 2025 to August 2026
- Distance
- 1,491 mi
- Carriers
- 3
This route lands a B+, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That rests on 2,781 DEN to BWI flights, of which United Airlines flew 839 at 82.2% on time.
Best time to fly DEN to BWI: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 95.8% of the time and Wednesday flights 81.3%, against 77.3% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.3%
Arrivals under 15 minutes late, of 2,736 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.97%
National rate is 1.89%
Best carrier
United
82.2% on time across 839 flights
These figures cover 2,781 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.
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Carrier by carrier
Which airline is most reliable on DEN to BWI
The choice of carrier is not cosmetic here. United Airlines arrives on time 82.2% of the time; Southwest Airlines manages 74.9%. Sample sizes sit next to every figure, because a two-point gap across 1,917 flights means less than a ten-point one.
| 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 | 1,917 | 74.9% | 51 min | 1.15% | C |
United leads Southwest by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on DEN to BWI
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Denver to Baltimore
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 3 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. DEN → IADDenver to Washington | United Airlines | 84.4% | 84.8% | 0.50% | 5am–8am, Wed | UA 1924 23:59 |
| 2. DEN → BWIDenver to Baltimore | United Airlines | 81.7% | 82.2% | 0.60% | 8am–11am, Wed | UA 1362 09:46 |
| 3. DEN → DCADenver to Washington | Frontier Airlines | 76.9% | 77.5% | 0.81% | 5am–8am, Sat | F9 686 07:35 |
| 4. DEN → BWIDenver to Baltimore | Southwest Airlines | 74.0% | 74.9% | 1.15% | 5am–8am, Wed | — |
| 5. DEN → IADDenver to Washington | Southwest Airlines | 67.0% | 67.7% | 1.01% | 8am–11am, Tue | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 37 points, against 7 points between the best and worst carrier.
- 5am–8am461 flights95.8%
- 8am–11am615 flights87.5%
- 11am–2pm286 flights73.7%
- 2pm–5pm439 flights70.3%
- 5pm–8pm664 flights58.5%
- 8pm–5am316 flights82.0%
Scale runs 50% to 100%.
The 5pm–8pm window is where this operation falls apart: 58.5% 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 5pm–8pm window is the busiest, with 664 flights scheduled in it.
Explore
Filter DEN to BWI by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On DEN to BWI, the best departure window is 5am–8am at 95.8% on time and the worst is 5pm–8pm at 58.5%, a wide gap of 37.3 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am95.8%
- 8–11am87.5%
- 11am–2pm73.7%
- 2–5pm70.3%
- 5–8pm58.5%
- 8pm–5am82.0%
best all US flightsScale 50% to 100%.
Across the year
When delays peak on this route
This route's year swings by 23 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 64.2% on time, 23 points below January, the best at 86.9%. 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. October was the busiest month here, with 269 flights.
Across the week, Wednesday is the strongest day at 81.3% on time and Thursday the weakest at 72.3%, a spread of 9 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 50% of the 32,000 delay minutes carriers reported here, and the remaining four split what is left.
- 50%Late-arriving aircraft
- 32%Carrier
- 17%National Airspace System
- 1%Extreme weather
50% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 32,000 reported delay minutes here, that single category outweighs weather by 47 to one. The split is drawn from 31,807 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 0.97% against a national 1.89%, which is ordinary. Diversions add another 0.65%.
Connections and stage length
What a delay here actually costs
6.0% 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 76.0% on time across 2,784 flights, within about 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 2,781 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.
Work out the risk of missing a connection in BWI after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 86.9% on time and June 64.2%, a swing of 23 points. If the dates move at all, move them out of June before you think about anything else. 2,736 completed flights over 12 months sit behind that.
Common questions
DEN to BWI questions
How often is DEN to BWI delayed?
Roughly 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 22.7% of the 2,781 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 50 minutes on average.
Which airline is most reliable on DEN to BWI?
United Airlines leads at 82.2% on time across 839 flights. Southwest Airlines is at the other end on 74.9%, a gap of 7 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 DEN to BWI?
The 5am–8am departure window is the strongest at 95.8% on time. The 5pm–8pm window is the weakest at 58.5%, 37 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 June delays on DEN to BWI?
June is the weakest month at 64.2% on time, compared with 86.9% in January. Across the year that is 23 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
- BWI to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- United Airlines on DEN to BWI82.2%
- Southwest Airlines on DEN to BWI74.9%
- DEN to PHX, a related route75.6%
- ATL to BWI, a related route75.2%
- DEN to SLC, a related route78.2%
- Frontier Airlines on-time record92.0%
- United Airlines on-time record82.2%
- Southwest Airlines on-time record74.9%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. DEN to BWI and BWI to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.