Carrier route record

UABWI→DEN

United Airlines · Baltimore to Denver

Flights: 902
Period: July 2025 to June 2026
Share of route: 31%
Carriers: 3

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

United on BWI to DEN earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 902 flights, with a median arrival 9 minutes early.

Set against the rest of the country, United's BWI to DEN record is 8 points better than the US average of 77.6%. That gap is worth roughly 80 fewer late arrivals for every thousand flights.

On time

85.6%

Arrivals under 15 minutes late, of 894 completed flights

Avg delay

77 min

Across delayed arrivals only, not all flights

Cancelled

0.55%

National rate is 1.81%

Whole route

75.6%

Every carrier on BWI to DEN, 2,867 flights

These figures cover 902 flights between July 2025 and June 2026. The median arrival is 9 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

United against every carrier on BWI to DEN

United flew 902 of the 2,867 flights on BWI to DEN, about 31% of it. Its 85.6% on time is 10 points better than the route as a whole, which runs 75.6%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from United at 85.6% to Frontier at 50.0%. 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 BWI to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines (this page)	902	85.6%	77 min	0.55%	A+
Southwest Airlines	1,905	71.7%	53 min	1.42%	C
Frontier Airlinesthin sample	60	50.0%	87 min	0.00%	F+

Flight by flight

United flight numbers on BWI to DEN

Departure window

When United runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 16 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–8am2 flights—
8am–11am534 flights91.9%
11am–2pm—
2pm–5pm364 flights76.1%
5pm–8pm—
8pm–5am2 flights—

Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 91.9% of the time, against 76.1% for the afternoon window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 534 flights scheduled in it.

Across the year

United on BWI to DEN through the year

Darker means more delays. Figures are on-time percentages.October best, June worst

June is the worst month at 70.0% on time, 24 points below October, the best at 93.5%. 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. August was the busiest month here, with 93 flights.

Across the week, Tuesday is the strongest day at 92.2% on time and Thursday the weakest at 81.1%. 11 points is a smaller lever than departure hour, but it is free.

Delay causes

Why United runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 9,968 reported delay minutes.

National Airspace System
38%
Late-arriving aircraft
27%
Carrier
18%
Extreme weather
17%

Extreme weather accounts for 17% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.7 times the usual weather exposure. The split is drawn from 9,968 reported delay minutes.

38% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,752 minutes out of 9,968, against a national NAS share of 21%.

Cancellations are rare at 0.55%, 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

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.

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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg is a different operation and performs like one: it runs 80.6% on time across 901 flights, 5 points below 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 5 points of difference.

One caution: this is a thin sample. 902 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 United on BWI to DEN

Put together: treat all of this as provisional. 902 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 85.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 894 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