Flight number record
UA 2456
United Airlines · Houston to Seattle
- Route
- IAH → SEA
- Departs
- 19:57
- Flights
- 280
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 2456, check with United Airlines.
UA 2456 sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land about 50 minutes behind schedule. That rests on 280 flights, with a median arrival 1 minute early.
Key figures
On time
74.5%
Arrivals under 15 minutes late, of 278 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.36%
National rate is 1.89%
1 hour+ late
6.8%
National rate is 8.3%
These figures cover 280 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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Schedule
When UA 2456 flies
UA 2456 flies IAH to SEA without a single fixed slot. Its most common scheduled departure was 19:57, used on 76 of 280 flights, with 19:50 (71 flights) and 19:55 (55 flights) next.
- Departs 19:5776 flights27.1%
- Departs 19:5071 flights25.4%
- Departs 19:5555 flights19.6%
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 19:57 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and UA 2456 runs 7 points better at 74.5%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
UA 2456 next to IAH to SEA
Every carrier on IAH to SEA combined arrived on time 80.7% of the time across 2,072 flights, so UA 2456 is 6 points behind it. United flew 1,230 flights on the same city pair under all its flight numbers, including this one, and those ran 79.9% on time. Across its whole network United Airlines managed 78.8%, which this flight trails by 4 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2456thin sample | 280 | 74.5% | 50 min | 0.36% | C+ |
| All United Airlines on IAH–SEA | 1,230 | 79.9% | 52 min | 0.08% | B+ |
| All carriers on IAH–SEA | 2,072 | 80.7% | 52 min | 0.24% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 2456 quarter by quarter
UA 2456 did not run the same all year. Its best quarter was Apr–Jun 2026 at 80.5% on time and its weakest Jul–Sep 2025 at 63.3%, a swing of 17 points on roughly 70 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 flights63.3%
- Oct–Dec 202590 flights74.2%
- Jan–Mar 202690 flights74.2%
- Apr–Jun 202641 flights80.5%
- Jul–Sep 202629 flights—
Scale runs 55% to 85%. Rows with fewer than 30 flights show a dash.
By weekday, UA 2456 did best on Tuesday at 88.2% on time and worst on Saturday at 69.2%. Each day rests on about 40 flights, so a gap of 19 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 2456 runs when it is late
The 71 late arrivals split 27 under half an hour, 25 between 30 and 60 minutes, and 19 an hour or more.
- 15+ min early67 flights24.1%
- Within 15 min140 flights50.4%
- 15–29 min late27 flights9.7%
- 30–59 min late25 flights9.0%
- 1–2 hours late16 flights5.8%
- 2+ hours late3 flights1.1%
Scale runs 0% to 100%.
Share of 278 completed flights by arrival against schedule.
A late pushback is often recovered here: of 71 departures that left 15 minutes late or more, 25 still arrived on time. In the other direction, 25 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 SEA.
The worst days
Worst days for UA 2456
The latest arrival of the period was on 7 March 2026, 4 hours 17 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 7 March 2026 | 4 hours 17 minutes | Late-arriving aircraft |
| 23 February 2026 | 2 hours 30 minutes | Carrier |
| 24 January 2026 | 2 hours 9 minutes | Carrier |
| 2 May 2026 | 1 hour 52 minutes | Late-arriving aircraft |
| 21 May 2026 | 1 hour 50 minutes | Carrier |
Delay causes
Why UA 2456 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 3,524 reported delay minutes.
- 35%Carrier
- 31%National Airspace System
- 29%Late-arriving aircraft
- 6%Extreme weather
The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,226 of the 3,524 delay minutes reported here. The split is drawn from 3,524 delay minutes reported on UA 2456.
Cancellations are rare at 0.36%, 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
6.8% 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 50 minutes, which a normal layover absorbs.
At 1,874 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 MCO to IAH (187), DCA to IAH (21) and BNA to IAH (15), but none flew often enough under UA 2456 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to IAH to SEA only.
One caution: this is a thin sample. 280 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 2456
For a booking, UA 2456 is one of the weaker ways to fly IAH to SEA: 6 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
- IAH to SEA, every carrier and departure
- SEA to IAH, the return direction
- Alaska Airlines 439 on the same route76.7%
- Alaska Airlines 453 on the same route87.0%
- George Bush Intercontinental (IAH) delay statistics
- Seattle-Tacoma International (SEA) 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.