Flight number record
UA 1023
United Airlines · Denver to Chicago
- Route
- DEN → ORD
- Departs
- 15:20
- Flights
- 364
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1023, check with United Airlines.
UA 1023 draws a D+. Roughly one flight in two arrives at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 364 flights, with a median arrival 7 minutes late.
The national on-time rate over the same period is 77.6%, so UA 1023 runs 18 points behind the country as a whole. Across a thousand flights that is about 178 extra late arrivals.
Key figures
On time
59.8%
Arrivals under 15 minutes late, of 361 completed flights
Avg delay
74 min
Across delayed arrivals only, not all flights
Cancelled
0.27%
National rate is 1.81%
1 hour+ late
11.4%
National rate is 8.1%
These figures cover 364 flights between July 2025 and June 2026. Beyond the headline rate, 11.4% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Schedule
When UA 1023 flies
UA 1023 flies DEN to ORD without a single fixed slot. Its most common scheduled departure was 15:20, used on 74 of 364 flights, with 14:45 (68 flights) and 14:44 (49 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 15:2074 flights20.3%
- Departs 14:4568 flights18.7%
- Departs 14:4449 flights13.5%
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 15:20 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and UA 1023 runs 13 points worse at 59.8%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
Against the route
UA 1023 next to DEN to ORD
Every carrier on DEN to ORD combined arrived on time 71.1% of the time across 6,161 flights, so UA 1023 is 11 points behind it. United flew 3,756 flights on the same city pair under all its flight numbers, including this one, and those ran 71.4% on time. Across its whole network United Airlines managed 79.0%, which this flight trails by 19 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1023thin sample | 364 | 59.8% | 74 min | 0.27% | D+ |
| All United Airlines on DEN–ORD | 3,756 | 71.4% | 79 min | 0.75% | C+ |
| All carriers on DEN–ORD | 6,161 | 71.1% | 88 min | 1.07% | C |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 1023 quarter by quarter
UA 1023 did not run the same all year. Its best quarter was Apr–Jun 2026 at 73.0% on time and its weakest Oct–Dec 2025 at 50.5%, a swing of 23 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 flights60.9%
- Oct–Dec 202591 flights50.5%
- Jan–Mar 202690 flights55.1%
- Apr–Jun 202691 flights73.0%
Scale runs 40% to 80%. Rows with fewer than 30 flights show a dash.
By weekday, UA 1023 did best on Monday at 66.7% on time and worst on Thursday at 44.0%. Each day rests on about 52 flights, so a gap of 23 points is worth noticing but could still narrow in another year.
Delay causes
Why UA 1023 runs late
One category carries most of the weight here. National Airspace System accounts for 65% of the 11,000 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.
- 65%National Airspace System
- 18%Late-arriving aircraft
- 9%Carrier
- 8%Extreme weather
65% 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 6,924 minutes out of 11,000, against a national NAS share of 21%. The split is drawn from 10,654 delay minutes reported on UA 1023.
Cancellations are rare at 0.27%, 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.4% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
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 ORD to IAD (55), SMF to DEN (41) and AUS to DEN (31), but none flew often enough under UA 1023 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to ORD 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 1023
For a booking, UA 1023 is one of the weaker ways to fly DEN to ORD: 11 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.
Related
Where to go next
- DEN to ORD, every carrier and departure
- ORD to DEN, the return direction
- United Airlines 2865 on the same route78.2%
- United Airlines 2329 on the same route82.2%
- United Airlines 617 on the same route66.5%
- United Airlines 1377 on the same route87.4%
- American Airlines 2771 on the same route87.5%
- United Airlines 2258 on the same route67.8%
- Denver International (DEN) delay statistics
- Chicago O'Hare International (ORD) 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
- How often a connection fails at the major US hubs
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.