Flight number record

UA 1510

United Airlines · Louisville to Denver

Route: SDF → DEN
Departs: 15:25
Flights: 364
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1510, check with United Airlines.

UA 1510 lands a B, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 364 flights, with a median arrival 9 minutes early.

On time

78.5%

Arrivals under 15 minutes late, of 358 completed flights

Avg delay

57 min

Across delayed arrivals only, not all flights

Cancelled

1.37%

National rate is 1.81%

1 hour+ late

6.4%

National rate is 8.1%

These figures cover 364 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.

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 90 of 364 flights, with 15:30 (68 flights) and 15:15 (53 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 15:2590 flights24.7%
Departs 15:3068 flights18.7%
Departs 15:1553 flights14.6%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

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 72.4%, and UA 1510 runs 6 points better at 78.5%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

UA 1510 next to SDF to DEN

Every carrier on SDF to DEN combined arrived on time 83.0% of the time across 1,103 flights, so UA 1510 is 5 points behind it. United flew 731 flights on the same city pair under all its flight numbers, including this one, and those ran 84.6% on time. Across its whole network United Airlines managed 79.0%, close to this flight's figure.

UA 1510 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1510thin sample	364	78.5%	57 min	1.37%	B
All United Airlines on SDF–DEN	731	84.6%	66 min	0.96%	B+
All carriers on SDF–DEN	1,103	83.0%	61 min	1.00%	B
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 1510 quarter by quarter

UA 1510 did not run the same all year. Its best quarter was Oct–Dec 2025 at 85.6% on time and its weakest Jul–Sep 2025 at 73.9%, a swing of 12 points on roughly 91 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 202592 flights73.9%
Oct–Dec 202591 flights85.6%
Jan–Mar 202690 flights79.3%
Apr–Jun 202691 flights75.3%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, UA 1510 did best on Monday at 88.2% on time and worst on Friday at 72.5%. Each day rests on about 52 flights, so a gap of 16 points is worth noticing but could still narrow in another year.

Delay causes

Why UA 1510 runs late

One category carries most of the weight here. Carrier accounts for 47% of the 4,390 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Carrier
47%
National Airspace System
34%
Late-arriving aircraft
16%
Extreme weather
3%

The largest share of delay minutes, 47%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 2,065 of the 4,390 delay minutes reported here. The split is drawn from 4,390 delay minutes reported on UA 1510.

Cancellations sit at 1.37% against a national 1.81%, which is ordinary. Diversions add another 0.27%.

Connections and routes

What a delay on this flight costs

6.4% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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. 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 same number turns up on one other city pair in the data, including DEN to PHL (62), 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. 364 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 78.5% on time with 1.37% cancelled over 364 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures