Flight number record

UA 2237

United Airlines · San Diego to Houston

Route: SAN → IAH
Departs: 11:58
Flights: 339
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 2237, check with United Airlines.

UA 2237 lands a B+, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 339 flights, with a median arrival 4 minutes early.

On time

78.9%

Arrivals under 15 minutes late, of 336 completed flights

Avg delay

56 min

Across delayed arrivals only, not all flights

Cancelled

0.29%

National rate is 1.81%

1 hour+ late

5.1%

National rate is 8.1%

These figures cover 339 flights between July 2025 and June 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.

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 83 of 339 flights, with 12:10 (53 flights) and 12:16 (45 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 11:5883 flights24.5%
Departs 12:1053 flights15.6%
Departs 12:1645 flights13.3%

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 11:58 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and UA 2237 runs level with that at 78.9%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

UA 2237 next to SAN to IAH

Every carrier on SAN to IAH combined arrived on time 84.5% of the time across 1,693 flights, so UA 2237 is 6 points behind it. Across its whole network United Airlines managed 79.0%, close to this flight's figure.

UA 2237 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 2237thin sample	339	78.9%	56 min	0.29%	B+
All United Airlines on SAN–IAH	1,693	84.5%	72 min	0.53%	B+
All carriers on SAN–IAH	1,693	84.5%	72 min	0.53%	B+
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 2237 quarter by quarter

Quarter by quarter UA 2237 held fairly steady: 77.4% in Jul–Sep 2025, 78.2% in Oct–Dec 2025, 84.3% in Jan–Mar 2026 and 75.8% in Apr–Jun 2026. A spread of 9 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202585 flights77.4%
Oct–Dec 202578 flights78.2%
Jan–Mar 202685 flights84.3%
Apr–Jun 202691 flights75.8%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, UA 2237 did best on Wednesday at 88.0% on time and worst on Sunday at 68.8%. Each day rests on about 48 flights, so a gap of 19 points is worth noticing but could still narrow in another year.

Delay causes

Why UA 2237 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 52% of the 3,998 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.

Late-arriving aircraft
52%
National Airspace System
29%
Carrier
19%

52% 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 3,998 reported delay minutes here, that single category outweighs weather by 52 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 3,998 delay minutes reported on UA 2237.

Cancellations are rare at 0.29%, below the national 1.81% 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

5.1% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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. 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 IAH to IAD (163), SFO to SAN (31) and IAH to MIA (21), 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. 339 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.

Where to go next

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.

Key figures