Carrier route record
UADEN→BHM
United Airlines · Denver to Birmingham
- Flights
- 123
- Period
- September 2025 to August 2026
- Share of route
- 10%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on DEN to BHM 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 about an hour on average. That rests on 123 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 604 at 79.2% on time.
The US average over the same twelve months is 77.3%, so there is little to separate United on DEN to BHM from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.2%
Arrivals under 15 minutes late, of 123 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
Whole route
72.5%
Every carrier on DEN to BHM, 1,236 flights
These figures cover 123 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
United against every carrier on DEN to BHM
United flew 123 of the 1,236 flights on DEN to BHM, about 10% of it. Its 77.2% on time is 5 points better than the route as a whole, which runs 72.5%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from SkyWest at 79.2% to Southwest at 63.3%.
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 79.2% of the time; Southwest Airlines manages 63.3%. Sample sizes sit next to every figure, because a two-point gap across 509 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 604 | 79.2% | 78 min | 0.33% | B+ |
| United Airlines (this page)thin sample | 123 | 77.2% | 56 min | 0.00% | B+ |
| Southwest Airlines | 509 | 63.3% | 63 min | 0.39% | D+ |
The spread between SkyWest and Southwest is 16 points, wide enough that it should decide the booking. On a hundred trips that is 16 more arrivals inside the on-time window.
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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 18 points, against 16 points between the best and worst carrier.
- 5am–8am—
- 8am–11am91 flights72.5%
- 11am–2pm32 flights90.6%
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am—
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 90.6% on time, ahead of 8am–11am at 72.5%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 8am–11am window is the busiest, with 91 flights scheduled in it.
Across the year
United on DEN to BHM through the year
- Apr–Jun 202661 flights72.1%
- Jul–Sep 202662 flights82.3%
Scale runs 65% to 90%.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 77.2% on time across 123 flights.
Split by quarter, United on DEN to BHM logged 61 flights in Apr–Jun 2026 and 62 flights in Jul–Sep 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 77.2% annual figure is the one to use.
Arrival by arrival
How late United on DEN to BHM runs when it is late
The 28 late arrivals split 13 under half an hour, 8 between 30 and 60 minutes, and 7 an hour or more.
- 15+ min early29 flights23.6%
- Within 15 min66 flights53.7%
- 15–29 min late13 flights10.6%
- 30–59 min late8 flights6.5%
- 1–2 hours late2 flights1.6%
- 2+ hours late5 flights4.1%
Scale runs 0% to 100%.
Share of 123 completed flights by arrival against schedule.
4 of 20 late departures made up the time and arrived on time, 20% of them. In the other direction, 12 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at BHM.
The worst days
Worst days for United on DEN to BHM
The latest arrival of the period was on 22 June 2026, 3 hours 10 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. Three of the five worst days fell in June 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 22 June 2026 | 3 hours 10 minutes | Late-arriving aircraft |
| 20 July 2026 | 3 hours 6 minutes | Carrier |
| 13 July 2026 | 2 hours 23 minutes | Late-arriving aircraft |
| 9 June 2026 | 2 hours 10 minutes | Late-arriving aircraft |
| 25 June 2026 | 2 hours 2 minutes | Carrier |
Delay causes
Why United runs late on this route
Late-arriving aircraft accounts for 49% of the 1,555 delay minutes carriers reported here, and the remaining four split what is left.
- 49%Late-arriving aircraft
- 27%Carrier
- 24%National Airspace System
49% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 1,555 reported delay minutes here, that single category outweighs weather by 49 to one. The split is drawn from 1,555 reported delay minutes.
Cancellations are rare at 0.00%, below the national 1.89% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
5.7% 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 about an hour, which a normal layover absorbs.
The 1,083 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 is a different operation and performs like one: it runs 72.1% on time across 123 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. 123 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 DEN to BHM
Put together: treat all of this as provisional. 123 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 77.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 123 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to BHM, every carrier
- United on BHM to DEN, the return leg
- SkyWest Airlines on DEN to BHM79.2%
- Southwest Airlines on DEN to BHM63.3%
- United Airlines network-wide record
- Denver International (DEN) delay statistics
- Same route, different airline: where the carrier you pick matters most
- 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.