Flight number record
UA 1803
United Airlines · Chicago to Denver
- Route
- ORD → DEN
- Departs
- 10:40
- Flights
- 297
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 1803, check with United Airlines.
UA 1803 earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 297 flights, with a median arrival 10 minutes early.
Set against the rest of the country, UA 1803's record is 7 points better than the US average of 77.3%. That gap is worth roughly 72 fewer late arrivals for every thousand flights.
Key figures
On time
84.5%
Arrivals under 15 minutes late, of 296 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
0.34%
National rate is 1.89%
1 hour+ late
5.7%
National rate is 8.3%
These figures cover 297 flights between September 2025 and August 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.
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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 297 flights, with 10:49 (53 flights) and 10:56 (43 flights) next.
- Departs 10:4070 flights23.6%
- Departs 10:4953 flights17.8%
- Departs 10:5643 flights14.5%
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 10:40 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and UA 1803 runs level with that at 84.5%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
UA 1803 next to ORD to DEN
Every carrier on ORD to DEN combined arrived on time 74.3% of the time across 6,118 flights, so UA 1803 is 10 points ahead of it. United flew 3,888 flights on the same city pair under all its flight numbers, including this one, and those ran 78.3% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 6 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1803thin sample | 297 | 84.5% | 56 min | 0.34% | B+ |
| All United Airlines on ORD–DEN | 3,888 | 78.3% | 76 min | 0.87% | B+ |
| All carriers on ORD–DEN | 6,118 | 74.3% | 78 min | 1.19% | C |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | 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 96.7% on time and its weakest Jan–Mar 2026 at 77.5%, a swing of 19 points on roughly 74 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 202592 flights82.6%
- Jan–Mar 202690 flights77.5%
- Apr–Jun 202685 flights89.4%
Scale runs 70% to 100%.
By weekday, UA 1803 ranged from 81.0% on Saturday to 87.8% on Friday. With about 42 flights behind each day, a spread of 7 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late UA 1803 runs when it is late
UA 1803 often beats the schedule: 106 of 296 completed flights, 36%, arrived 15 minutes or more early. The 46 late arrivals split 20 under half an hour, 9 between 30 and 60 minutes, and 17 an hour or more.
- 15+ min early106 flights35.8%
- Within 15 min144 flights48.6%
- 15–29 min late20 flights6.8%
- 30–59 min late9 flights3.0%
- 1–2 hours late13 flights4.4%
- 2+ hours late4 flights1.4%
Scale runs 0% to 100%.
Share of 296 completed flights by arrival against schedule.
13 of 45 late departures made up the time and arrived on time, 29% of them. 14 flights left on time and still arrived late.
The worst days
Worst days for UA 1803
The latest arrival of the period was on 7 December 2025, 3 hours 42 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The five worst days are spread across December, February, November, October and March, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 7 December 2025 | 3 hours 42 minutes | Late-arriving aircraft |
| 17 February 2026 | 2 hours 44 minutes | National Airspace System |
| 13 November 2025 | 2 hours 40 minutes | Carrier |
| 25 October 2025 | 2 hours 3 minutes | Carrier |
| 18 March 2026 | 1 hour 45 minutes | National Airspace System |
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 2,551 reported delay minutes.
- 38%National Airspace System
- 31%Carrier
- 22%Late-arriving aircraft
- 9%Extreme weather
38% 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 972 minutes out of 2,551, against a national NAS share of 21%. The split is drawn from 2,551 delay minutes reported on UA 1803.
Cancellations are rare at 0.34%, 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
5.7% 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 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.
The same number turns up on seven other city pairs in the data, including PIT to ORD (214), RDU to ORD (101) 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. 297 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, read UA 1803 as 84.5% on time with 0.34% cancelled over 297 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- ORD to DEN, every carrier and departure
- DEN to ORD, the return direction
- United Airlines 767 on the same route69.5%
- American Airlines 1387 on the same route55.1%
- Frontier Airlines 1483 on the same route65.2%
- Chicago O'Hare International (ORD) delay statistics
- 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
- The best time of day to fly, according to 7.05 million flight records
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.