Flight number record
UA 1510
United Airlines · Louisville to Denver
- Route
- SDF → DEN
- Departs
- 15:25
- Flights
- 363
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 1510, check with United Airlines.
UA 1510 lands a B, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 363 flights, with a median arrival 11 minutes early.
Key figures
On time
80.7%
Arrivals under 15 minutes late, of 353 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
1.38%
National rate is 1.89%
1 hour+ late
6.5%
National rate is 8.3%
These figures cover 363 flights between September 2025 and August 2026. The median arrival is 11 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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Schedule
When UA 1510 flies
UA 1510 flies SDF to DEN without a single fixed slot. Its most common scheduled departure was 15:25, used on 102 of 363 flights, with 15:30 (55 flights) and 15:15 (53 flights) next.
- Departs 15:25102 flights28.1%
- Departs 15:3055 flights15.2%
- Departs 15:1553 flights14.6%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 15:25 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and UA 1510 runs 9 points better at 80.7%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
UA 1510 next to SDF to DEN
Every carrier on SDF to DEN combined arrived on time 84.1% of the time across 1,096 flights, so UA 1510 is 3 points behind it. United flew 730 flights on the same city pair under all its flight numbers, including this one, and those ran 85.8% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1510thin sample | 363 | 80.7% | 60 min | 1.38% | B |
| All United Airlines on SDF–DEN | 730 | 85.8% | 72 min | 0.96% | A+ |
| All carriers on SDF–DEN | 1,096 | 84.1% | 65 min | 1.00% | B |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 1510 quarter by quarter
UA 1510 did not run the same all year. Its best quarter was Jul–Sep 2025 at 86.7% on time and its weakest Apr–Jun 2026 at 75.3%, a swing of 11 points on roughly 73 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights86.7%
- Oct–Dec 202591 flights85.6%
- Jan–Mar 202690 flights79.3%
- Apr–Jun 202691 flights75.3%
- Jul–Sep 202661 flights80.7%
Scale runs 65% to 90%.
By weekday, UA 1510 did best on Monday at 88.5% on time and worst on Thursday at 74.5%. Each day rests on about 52 flights, so a gap of 14 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 1510 runs when it is late
UA 1510 often beats the schedule: 133 of 353 completed flights, 38%, arrived 15 minutes or more early. The 68 late arrivals split 29 under half an hour, 16 between 30 and 60 minutes, and 23 an hour or more.
- 15+ min early133 flights37.7%
- Within 15 min152 flights43.1%
- 15–29 min late29 flights8.2%
- 30–59 min late16 flights4.5%
- 1–2 hours late14 flights4.0%
- 2+ hours late9 flights2.5%
Scale runs 0% to 100%.
Share of 353 completed flights by arrival against schedule.
17 of 63 late departures made up the time and arrived on time, 27% of them. In the other direction, 22 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 DEN.
The worst days
Worst days for UA 1510
The latest arrival of the period was on 19 February 2026, 5 hours 16 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in February 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 19 February 2026 | 5 hours 16 minutes | Carrier |
| 17 February 2026 | 4 hours 9 minutes | National Airspace System |
| 8 March 2026 | 3 hours 39 minutes | Carrier |
| 30 December 2025 | 2 hours 21 minutes | Carrier |
| 13 February 2026 | 2 hours 15 minutes | Carrier |
Delay causes
Why UA 1510 runs late
Carrier accounts for 42% of the 4,098 delay minutes carriers reported here, and the remaining four split what is left.
- 42%Carrier
- 32%National Airspace System
- 22%Late-arriving aircraft
- 4%Extreme weather
The largest share of delay minutes, 42%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,727 of the 4,098 delay minutes reported here. The split is drawn from 4,098 delay minutes reported on UA 1510.
Cancellations sit at 1.38% against a national 1.89%, which is ordinary. Diversions add another 1.38%.
Connections and routes
What a delay on this flight costs
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 an hour, which a normal layover absorbs.
The 1,024 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 same number turns up on one other city pair in the data, including DEN to PHL (123), but none flew often enough under UA 1510 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SDF to DEN only.
One caution: this is a thin sample. 363 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 UA 1510
For a booking, read UA 1510 as 80.7% on time with 1.38% cancelled over 363 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SDF to DEN, every carrier and departure
- DEN to SDF, the return direction
- Denver International (DEN) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.