Flight number record
UA 2135
United Airlines · Seattle to Houston
- Route
- SEA → IAH
- Departs
- 07:00
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 2135, check with United Airlines.
UA 2135 earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 16 points better than the national rate of 77.3%. When something does go wrong the average delay runs close to two hours. That rests on 364 flights, with a median arrival 16 minutes early.
Set against the rest of the country, UA 2135's record is 16 points better than the US average of 77.3%. That gap is worth roughly 155 fewer late arrivals for every thousand flights.
Key figures
On time
92.8%
Arrivals under 15 minutes late, of 362 completed flights
Avg delay
101 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.89%
1 hour+ late
2.5%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. The median arrival is 16 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 2135 flies
UA 2135 flies SEA to IAH without a single fixed slot. Its most common scheduled departure was 07:00, used on 93 of 364 flights, with 07:05 (91 flights) and 07:10 (78 flights) next.
- Departs 07:0093 flights25.5%
- Departs 07:0591 flights25.0%
- Departs 07:1078 flights21.4%
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 07:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and UA 2135 runs 4 points better at 92.8%. 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 2135 next to SEA to IAH
Every carrier on SEA to IAH combined arrived on time 84.0% of the time across 2,071 flights, so UA 2135 is 9 points ahead of it. United flew 1,230 flights on the same city pair under all its flight numbers, including this one, and those ran 87.9% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 14 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2135thin sample | 364 | 92.8% | 101 min | 0.55% | A+ |
| All United Airlines on SEA–IAH | 1,230 | 87.9% | 78 min | 0.16% | A+ |
| All carriers on SEA–IAH | 2,071 | 84.0% | 61 min | 0.29% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 2135 quarter by quarter
UA 2135 did not run the same all year. Its best quarter was Jul–Sep 2025 at 100.0% on time and its weakest Apr–Jun 2026 at 89.0%, a swing of 11 points on roughly 73 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 flights100.0%
- Oct–Dec 202592 flights91.3%
- Jan–Mar 202690 flights96.6%
- Apr–Jun 202691 flights89.0%
- Jul–Sep 202661 flights91.8%
Scale runs 80% to 100%.
By weekday, UA 2135 did best on Sunday at 100.0% on time and worst on Saturday at 84.3%. Each day rests on about 52 flights, so a gap of 16 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 2135 runs when it is late
UA 2135 often beats the schedule: 193 of 362 completed flights, 53%, arrived 15 minutes or more early. Most of the lateness is short. 13 of the 26 late arrivals were under half an hour behind, and 9 reached an hour or more.
- 15+ min early193 flights53.3%
- Within 15 min143 flights39.5%
- 15–29 min late13 flights3.6%
- 30–59 min late4 flights1.1%
- 1–2 hours late4 flights1.1%
- 2+ hours late5 flights1.4%
Scale runs 0% to 100%.
Share of 362 completed flights by arrival against schedule.
A late pushback is often recovered here: of 21 departures that left 15 minutes late or more, 8 still arrived on time. 13 flights left on time and still arrived late.
The worst days
Worst days for UA 2135
The latest arrival of the period was on 30 June 2026, 10 hours 42 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 30 June 2026 | 10 hours 42 minutes | Carrier |
| 27 December 2025 | 8 hours 24 minutes | Carrier |
| 1 November 2025 | 5 hours 32 minutes | Late-arriving aircraft |
| 12 May 2026 | 3 hours 52 minutes | Carrier |
| 12 November 2025 | 2 hours 41 minutes | Late-arriving aircraft |
Delay causes
Why UA 2135 runs late
Carrier accounts for 69% of the 2,632 delay minutes carriers reported here, and the remaining four split what is left.
- 69%Carrier
- 18%Late-arriving aircraft
- 13%National Airspace System
The largest share of delay minutes, 69%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,812 of the 2,632 delay minutes reported here. The split is drawn from 2,632 delay minutes reported on UA 2135.
Cancellations are rare at 0.55%, 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
Badly late arrivals are rare here: only 2.5% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
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 IAH to FLL (165), IAH to ORD (137) and ORD to DCA (55), but none flew often enough under UA 2135 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SEA to IAH 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 2135
For a booking, UA 2135 has one of the better records a US domestic flight can show: 92.8% on time and 0.55% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- SEA to IAH, every carrier and departure
- IAH to SEA, the return direction
- Alaska Airlines 438 on the same route70.6%
- Alaska Airlines 398 on the same route84.5%
- Seattle-Tacoma International (SEA) delay statistics
- 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
- 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.