Flight number record
UA 1583
United Airlines · Las Vegas to Chicago
- Route
- LAS → ORD
- Departs
- 10:25
- Flights
- 310
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 1583, check with United Airlines.
UA 1583 lands a B+, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 310 flights, with a median arrival 8 minutes early.
Key figures
On time
80.1%
Arrivals under 15 minutes late, of 306 completed flights
Avg delay
69 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
1 hour+ late
6.5%
National rate is 8.3%
These figures cover 310 flights between September 2025 and August 2026. The median arrival is 8 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 1583 flies
UA 1583 flies LAS to ORD without a single fixed slot. Its most common scheduled departure was 10:25, used on 82 of 310 flights, with 11:00 (56 flights) and 10:43 (53 flights) next.
- Departs 10:2582 flights26.5%
- Departs 11:0056 flights18.1%
- Departs 10:4353 flights17.1%
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 10:25 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and UA 1583 runs 4 points worse at 80.1%. 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 1583 next to LAS to ORD
Every carrier on LAS to ORD combined arrived on time 75.6% of the time across 5,148 flights, so UA 1583 is 5 points ahead of it. United flew 2,354 flights on the same city pair under all its flight numbers, including this one, and those ran 78.2% on time. Across its whole network United Airlines managed 78.8%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1583thin sample | 310 | 80.1% | 69 min | 0.00% | B+ |
| All United Airlines on LAS–ORD | 2,354 | 78.2% | 76 min | 0.34% | B+ |
| All carriers on LAS–ORD | 5,148 | 75.6% | 88 min | 1.24% | B |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 1583 quarter by quarter
UA 1583 did not run the same all year. Its best quarter was Apr–Jun 2026 at 86.5% on time and its weakest Jul–Sep 2026 at 70.5%, a swing of 16 points on roughly 78 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.
- Oct–Dec 202567 flights84.8%
- Jan–Mar 202690 flights76.7%
- Apr–Jun 202691 flights86.5%
- Jul–Sep 202662 flights70.5%
Scale runs 60% to 90%.
By weekday, UA 1583 did best on Saturday at 92.9% on time and worst on Sunday at 66.7%. Each day rests on about 44 flights, so a gap of 26 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 1583 runs when it is late
UA 1583 often beats the schedule: 87 of 306 completed flights, 28%, arrived 15 minutes or more early. The 61 late arrivals split 30 under half an hour, 11 between 30 and 60 minutes, and 20 an hour or more.
- 15+ min early87 flights28.4%
- Within 15 min158 flights51.6%
- 15–29 min late30 flights9.8%
- 30–59 min late11 flights3.6%
- 1–2 hours late11 flights3.6%
- 2+ hours late9 flights2.9%
Scale runs 0% to 100%.
Share of 306 completed flights by arrival against schedule.
5 of 34 late departures made up the time and arrived on time, 15% of them. In the other direction, 32 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at ORD.
The worst days
Worst days for UA 1583
The latest arrival of the period was on 27 July 2026, 5 hours 53 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 27 July 2026 | 5 hours 53 minutes | National Airspace System |
| 11 June 2026 | 5 hours 16 minutes | National Airspace System |
| 15 March 2026 | 4 hours 11 minutes | National Airspace System |
| 2 April 2026 | 4 hours 1 minute | Extreme weather |
| 10 June 2026 | 3 hours 53 minutes | National Airspace System |
Delay causes
Why UA 1583 runs late
National Airspace System accounts for 65% of the 4,207 delay minutes carriers reported here, and the remaining four split what is left.
- 65%National Airspace System
- 15%Carrier
- 15%Late-arriving aircraft
- 5%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 2,715 minutes out of 4,207, against a national NAS share of 21%. The split is drawn from 4,207 delay minutes reported on UA 1583.
Cancellations are rare at 0.00%, below the national 1.89% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
6.5% 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 a little over an hour, which a normal layover absorbs.
At 1,514 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The same number turns up on five other city pairs in the data, including ORD to RIC (159), ORD to BWI (55) and ORD to TYS (37), but none flew often enough under UA 1583 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to LAS to ORD only.
One caution: this is a thin sample. 310 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 1583
For a booking, read UA 1583 as 80.1% on time with 0.00% cancelled over 310 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- LAS to ORD, every carrier and departure
- ORD to LAS, the return direction
- United Airlines 664 on the same route86.2%
- United Airlines 2102 on the same route90.7%
- American Airlines 2258 on the same route88.1%
- United Airlines 706 on the same route65.0%
- Harry Reid International (LAS) 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
- Worst months to fly in the US, ranked by the data
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.