Flight number record

UA 1803

United Airlines · Chicago to Denver

Route: ORD → DEN
Departs: 10:40
Flights: 359
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1803, check with United Airlines.

UA 1803 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 about an hour. That rests on 359 flights, with a median arrival 10 minutes early.

Set against the rest of the country, UA 1803's record is 8 points better than the US average of 77.6%. That gap is worth roughly 79 fewer late arrivals for every thousand flights.

On time

85.5%

Arrivals under 15 minutes late, of 358 completed flights

Avg delay

59 min

Across delayed arrivals only, not all flights

Cancelled

0.28%

National rate is 1.81%

1 hour+ late

5.3%

National rate is 8.1%

These figures cover 359 flights between July 2025 and June 2026. The median arrival is 10 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 1803 flies

UA 1803 flies ORD to DEN without a single fixed slot. Its most common scheduled departure was 10:40, used on 70 of 359 flights, with 10:56 (57 flights) and 10:49 (53 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 10:4070 flights19.5%
Departs 10:5657 flights15.9%
Departs 10:4953 flights14.8%

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 10:40 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and UA 1803 runs level with that at 85.5%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

UA 1803 next to ORD to DEN

Every carrier on ORD to DEN combined arrived on time 74.2% of the time across 6,169 flights, so UA 1803 is 11 points ahead of it. United flew 3,758 flights on the same city pair under all its flight numbers, including this one, and those ran 77.4% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 7 points.

UA 1803 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1803thin sample	359	85.5%	59 min	0.28%	A+
All United Airlines on ORD–DEN	3,758	77.4%	73 min	0.93%	B+
All carriers on ORD–DEN	6,169	74.2%	77 min	1.23%	C
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 1803 quarter by quarter

UA 1803 did not run the same all year. Its best quarter was Jul–Sep 2025 at 92.4% on time and its weakest Jan–Mar 2026 at 77.5%, a swing of 15 points on roughly 90 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 flights92.4%
Oct–Dec 202592 flights82.6%
Jan–Mar 202690 flights77.5%
Apr–Jun 202685 flights89.4%

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, UA 1803 ranged from 80.4% on Saturday to 88.2% on Thursday. With about 51 flights behind each day, a spread of 8 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why UA 1803 runs late

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 3,065 reported delay minutes.

National Airspace System
34%
Carrier
33%
Late-arriving aircraft
25%
Extreme weather
8%

34% 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 1,044 minutes out of 3,065, against a national NAS share of 21%. The split is drawn from 3,065 delay minutes reported on UA 1803.

Cancellations are rare at 0.28%, 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 routes

What a delay on this flight costs

5.3% 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 888 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 seven other city pairs in the data, including PIT to ORD (193), RDU to ORD (111) and DEN to HDN (58), but none flew often enough under UA 1803 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ORD to DEN only.

One caution: this is a thin sample. 359 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 1803

For a booking, UA 1803 has one of the better records a US domestic flight can show: 85.5% on time and 0.28% 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures