Flight number record
UA 2237
United Airlines · San Diego to Houston
- Route
- SAN → IAH
- Departs
- 11:58
- Flights
- 345
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 2237, check with United Airlines.
UA 2237 lands a B+, level with the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 345 flights, with a median arrival 4 minutes early.
Key figures
On time
77.8%
Arrivals under 15 minutes late, of 342 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
0.29%
National rate is 1.89%
1 hour+ late
5.8%
National rate is 8.3%
These figures cover 345 flights between September 2025 and August 2026. The median arrival is 4 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 2237 flies
UA 2237 flies SAN to IAH without a single fixed slot. Its most common scheduled departure was 11:58, used on 81 of 345 flights, with 12:10 (53 flights) and 12:16 (45 flights) next.
- Departs 11:5881 flights23.5%
- Departs 12:1053 flights15.4%
- Departs 12:1645 flights13.0%
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 11:58 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and UA 2237 runs level with that at 77.8%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
UA 2237 next to SAN to IAH
Every carrier on SAN to IAH combined arrived on time 83.9% of the time across 1,686 flights, so UA 2237 is 6 points behind it. 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 2237thin sample | 345 | 77.8% | 59 min | 0.29% | B+ |
| All United Airlines on SAN–IAH | 1,686 | 83.9% | 70 min | 0.30% | B+ |
| All carriers on SAN–IAH | 1,686 | 83.9% | 70 min | 0.30% | B+ |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 2237 quarter by quarter
UA 2237 did not run the same all year. Its best quarter was Jan–Mar 2026 at 84.3% on time and its weakest Jul–Sep 2026 at 68.3%, a swing of 16 points on roughly 69 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 flights83.3%
- Oct–Dec 202578 flights78.2%
- Jan–Mar 202685 flights84.3%
- Apr–Jun 202691 flights75.8%
- Jul–Sep 202661 flights68.3%
Scale runs 60% to 90%.
By weekday, UA 2237 did best on Wednesday at 87.8% on time and worst on Thursday at 69.4%. Each day rests on about 49 flights, so a gap of 18 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late UA 2237 runs when it is late
The 76 late arrivals split 28 under half an hour, 28 between 30 and 60 minutes, and 20 an hour or more.
- 15+ min early70 flights20.5%
- Within 15 min196 flights57.3%
- 15–29 min late28 flights8.2%
- 30–59 min late28 flights8.2%
- 1–2 hours late11 flights3.2%
- 2+ hours late9 flights2.6%
Scale runs 0% to 100%.
Share of 342 completed flights by arrival against schedule.
9 of 68 late departures made up the time and arrived on time, 13% of them. 17 flights left on time and still arrived late.
The worst days
Worst days for UA 2237
The latest arrival of the period was on 29 June 2026, 8 hours 20 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 29 June 2026 | 8 hours 20 minutes | Late-arriving aircraft |
| 22 September 2025 | 3 hours 19 minutes | Late-arriving aircraft |
| 13 July 2026 | 3 hours 13 minutes | Late-arriving aircraft |
| 21 June 2026 | 2 hours 52 minutes | Late-arriving aircraft |
| 9 July 2026 | 2 hours 28 minutes | Late-arriving aircraft |
Delay causes
Why UA 2237 runs late
Late-arriving aircraft accounts for 53% of the 4,512 delay minutes carriers reported here, and the remaining four split what is left.
- 53%Late-arriving aircraft
- 26%National Airspace System
- 20%Carrier
53% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,512 reported delay minutes here, that single category outweighs weather by 53 to one. The split is drawn from 4,512 delay minutes reported on UA 2237.
Cancellations are rare at 0.29%, 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
5.8% 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 an hour, which a normal layover absorbs.
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 seven other city pairs in the data, including IAH to IAD (114), IAH to DTW (38) and SFO to SAN (31), but none flew often enough under UA 2237 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SAN to IAH only.
One caution: this is a thin sample. 345 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 2237
For a booking, UA 2237 is one of the weaker ways to fly SAN to IAH: 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
- SAN to IAH, every carrier and departure
- IAH to SAN, the return direction
- San Diego International (SAN) 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
- 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.