Flight number record
UA 2491
United Airlines · Houston to San Diego
- Route
- IAH → SAN
- Departs
- 09:30
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 2491, check with United Airlines.
UA 2491 earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 50 minutes. That rests on 365 flights, with a median arrival 10 minutes early.
Set against the rest of the country, UA 2491's record is 7 points better than the US average of 77.3%. That gap is worth roughly 72 fewer late arrivals for every thousand flights.
Key figures
On time
84.5%
Arrivals under 15 minutes late, of 361 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.27%
National rate is 1.89%
1 hour+ late
4.2%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. The median arrival is 10 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.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Schedule
When UA 2491 flies
UA 2491 flies IAH to SAN without a single fixed slot. Its most common scheduled departure was 09:30, used on 289 of 365 flights, with 09:31 (54 flights) next.
- Departs 09:30289 flights79.2%
- Departs 09:3154 flights14.8%
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 09:30 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and UA 2491 runs level with that at 84.5%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
UA 2491 next to IAH to SAN
Every carrier on IAH to SAN combined arrived on time 81.0% of the time across 1,686 flights, so UA 2491 is 4 points ahead of it. Across its whole network United Airlines managed 78.8%, which this flight beats by 6 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 2491 | 365 | 84.5% | 51 min | 0.27% | B+ |
| All United Airlines on IAH–SAN | 1,686 | 81.0% | 55 min | 0.18% | B+ |
| All carriers on IAH–SAN | 1,686 | 81.0% | 55 min | 0.18% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 2491 quarter by quarter
UA 2491 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Jul–Sep 2026 at 73.3%, a swing of 20 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 flights93.3%
- Oct–Dec 202592 flights87.0%
- Jan–Mar 202690 flights89.8%
- Apr–Jun 202691 flights81.3%
- Jul–Sep 202662 flights73.3%
Scale runs 65% to 100%.
By weekday, UA 2491 did best on Tuesday at 94.2% on time and worst on Thursday at 74.0%. Each day rests on about 52 flights, so a gap of 20 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 2491 runs when it is late
UA 2491 often beats the schedule: 130 of 361 completed flights, 36%, arrived 15 minutes or more early. The 56 late arrivals split 19 under half an hour, 22 between 30 and 60 minutes, and 15 an hour or more.
- 15+ min early130 flights36.0%
- Within 15 min175 flights48.5%
- 15–29 min late19 flights5.3%
- 30–59 min late22 flights6.1%
- 1–2 hours late11 flights3.0%
- 2+ hours late4 flights1.1%
Scale runs 0% to 100%.
Share of 361 completed flights by arrival against schedule.
14 of 61 late departures made up the time and arrived on time, 23% of them. 9 flights left on time and still arrived late.
The worst days
Worst days for UA 2491
The latest arrival of the period was on 22 September 2025, 3 hours 14 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 22 September 2025 | 3 hours 14 minutes | Late-arriving aircraft |
| 21 June 2026 | 2 hours 52 minutes | Late-arriving aircraft |
| 13 December 2025 | 2 hours 26 minutes | Late-arriving aircraft |
| 9 June 2026 | 2 hours 11 minutes | Late-arriving aircraft |
| 19 August 2026 | 1 hour 36 minutes | Carrier |
Delay causes
Why UA 2491 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 2,835 reported delay minutes.
- 38%National Airspace System
- 36%Carrier
- 26%Late-arriving aircraft
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,031 of the 2,835 delay minutes reported here. The split is drawn from 2,835 delay minutes reported on UA 2491.
Cancellations are rare at 0.27%, 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 4.2% 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.
The 1,303 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.
The same number turns up on four other city pairs in the data, including TPA to IAH (237), PIT to IAH (41) and SAN to DEN (37), but none flew often enough under UA 2491 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to IAH to SAN only.
One caution: this is a thin sample. 365 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 2491
For a booking, read UA 2491 as 84.5% on time with 0.27% cancelled over 365 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- IAH to SAN, every carrier and departure
- SAN to IAH, the return direction
- George Bush Intercontinental (IAH) delay statistics
- San Diego International (SAN) 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.