Flight number record

UA 1505

United Airlines · Seattle to Denver

Route: SEA → DEN
Departs: 08:40
Flights: 363
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s UA 1505, check with United Airlines.

UA 1505 earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 14 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 2.2 hours. That rests on 363 flights, with a median arrival 12 minutes early.

Set against the rest of the country, UA 1505's record is 14 points better than the US average of 77.3%. That gap is worth roughly 138 fewer late arrivals for every thousand flights.

On time

91.1%

Arrivals under 15 minutes late, of 360 completed flights

Avg delay

132 min

Across delayed arrivals only, not all flights

Cancelled

0.83%

National rate is 1.89%

1 hour+ late

5.0%

National rate is 8.3%

These figures cover 363 flights between September 2025 and August 2026. The median arrival is 12 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.

Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.

Schedule

When UA 1505 flies

UA 1505 flies SEA to DEN without a single fixed slot. Its most common scheduled departure was 08:40, used on 74 of 363 flights, with 08:56 (64 flights) next.

Departs 08:4074 flights20.4%
Departs 08:5664 flights17.6%

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 08:40 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and UA 1505 runs 7 points better at 91.1%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.

Against the route

UA 1505 next to SEA to DEN

Every carrier on SEA to DEN combined arrived on time 78.3% of the time across 6,333 flights, so UA 1505 is 13 points ahead of it. United flew 1,910 flights on the same city pair under all its flight numbers, including this one, and those ran 88.2% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 12 points.

UA 1505 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1505thin sample	363	91.1%	132 min	0.83%	A+
All United Airlines on SEA–DEN	1,910	88.2%	74 min	0.58%	A+
All carriers on SEA–DEN	6,333	78.3%	58 min	0.68%	B+
United Airlines, whole network	830,825	78.8%	73 min	1.02%	B

Across the year

UA 1505 quarter by quarter

UA 1505 did not run the same all year. Its best quarter was Jul–Sep 2025 at 96.7% on time and its weakest Jan–Mar 2026 at 85.2%, a swing of 12 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 flights96.7%
Oct–Dec 202590 flights93.3%
Jan–Mar 202690 flights85.2%
Apr–Jun 202691 flights93.3%
Jul–Sep 202662 flights90.3%

Scale runs 75% to 100%.

By weekday, UA 1505 ranged from 88.0% on Sunday to 98.0% on Thursday. With about 52 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.

Arrival by arrival

How late UA 1505 runs when it is late

UA 1505 often beats the schedule: 153 of 360 completed flights, 43%, arrived 15 minutes or more early. When UA 1505 is late it tends to be very late: 18 of its 32 late arrivals were an hour or more behind, and 11 were two hours or more.

15+ min early153 flights42.5%
Within 15 min175 flights48.6%
15–29 min late9 flights2.5%
30–59 min late5 flights1.4%
1–2 hours late7 flights1.9%
2+ hours late11 flights3.1%

Scale runs 0% to 100%.

Share of 360 completed flights by arrival against schedule.

7 of 33 late departures made up the time and arrived on time, 21% of them. Only 6 left on time and still arrived late.

The worst days

Worst days for UA 1505

The latest arrival of the period was on 12 August 2026, 12 hours 4 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across August, December, February and March, with no single month standing out.

The latest arrivals of UA 1505 in the period
Date	Arrived late by	Largest filed cause
12 August 2026	12 hours 4 minutes	Carrier
15 December 2025	10 hours 23 minutes	Late-arriving aircraft
9 February 2026	4 hours 30 minutes	Carrier
13 March 2026	4 hours 26 minutes	Extreme weather
31 December 2025	4 hours 16 minutes	Extreme weather

Delay causes

Why UA 1505 runs late

Carrier accounts for 47% of the 4,223 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
47%
Late-arriving aircraft
29%
National Airspace System
13%
Extreme weather
11%

Extreme weather accounts for 11% 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 quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 1.9 times the usual weather exposure. The split is drawn from 4,223 delay minutes reported on UA 1505.

Cancellations are rare at 0.83%, below the national 1.89% 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 routes

What a delay on this flight costs

5.0% 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 about 2.2 hours, 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.

UA 1505 is not only a SEA to DEN flight. It also flew DEN to EWR (320 flights, 69.0% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.

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.

Other routes flown as UA 1505
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
DEN to EWRthin sample	320	69.0%	90 min	1.88%	C

What to do with this

Booking UA 1505

For a booking, UA 1505 has one of the better records a US domestic flight can show: 91.1% on time and 0.83% cancelled. That is a base rate, not a promise about any single 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, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures