Flight number record
UA 1563
United Airlines · Houston to Ontario
- Route
- IAH → ONT
- Departs
- 20:15
- Flights
- 323
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1563, check with United Airlines.
UA 1563 lands a B+, level with the national rate of 77.6%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 323 flights, with a median arrival 5 minutes early.
Key figures
On time
77.0%
Arrivals under 15 minutes late, of 322 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.81%
1 hour+ late
9.3%
National rate is 8.1%
These figures cover 323 flights between July 2025 and June 2026. Beyond the headline rate, 9.3% 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 1563 flies
UA 1563 flies IAH to ONT without a single fixed slot. Its most common scheduled departure was 20:15, used on 73 of 323 flights, with 20:17 (48 flights) and 20:31 (41 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 20:1573 flights22.6%
- Departs 20:1748 flights14.9%
- Departs 20:3141 flights12.7%
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 20:15 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and UA 1563 runs 7 points better at 77.0%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Against the route
UA 1563 next to IAH to ONT
Every carrier on IAH to ONT combined arrived on time 75.7% of the time across 538 flights, so UA 1563 is about level with it. Across its whole network United Airlines managed 79.0%, which this flight trails by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1563thin sample | 323 | 77.0% | 68 min | 0.00% | B+ |
| All United Airlines on IAH–ONT | 365 | 77.7% | 68 min | 0.00% | B+ |
| All carriers on IAH–ONT | 538 | 75.7% | 63 min | 0.19% | B+ |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 1563 quarter by quarter
UA 1563 did not run the same all year. Its best quarter was Jan–Mar 2026 at 87.4% on time and its weakest Jul–Sep 2025 at 64.8%, a swing of 23 points on roughly 81 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 202554 flights64.8%
- Oct–Dec 202591 flights70.0%
- Jan–Mar 202687 flights87.4%
- Apr–Jun 202691 flights81.3%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
By weekday, UA 1563 ranged from 73.9% on Thursday to 84.1% on Tuesday. With about 46 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.
Delay causes
Why UA 1563 runs late
One category carries most of the weight here. Late-arriving aircraft accounts for 57% of the 5,054 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.
- 57%Late-arriving aircraft
- 32%Carrier
- 8%National Airspace System
- 4%Extreme weather
57% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 5,054 reported delay minutes here, that single category outweighs weather by 15 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 5,054 delay minutes reported on UA 1563.
Cancellations are rare at 0.00%, below the national 1.81% 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.3% 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 1,334 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 five other city pairs in the data, including PIT to IAH (66), TPA to IAH (32) and SEA to IAH (31), but none flew often enough under UA 1563 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to IAH to ONT only.
One caution: this is a thin sample. 323 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 1563
For a booking, read UA 1563 as 77.0% on time with 0.00% cancelled over 323 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- George Bush Intercontinental (IAH) 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
- Why the first flight of the morning is statistically safest
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.