Route reliability record
SAN→IAH
San Diego to Houston
- Flights
- 1,686
- Period
- September 2025 to August 2026
- Distance
- 1,303 mi
- Carriers
- 1
This route lands a B+, 7 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 1,686 SAN to IAH flights, with a median arrival 7 minutes early.
Best time to fly SAN to IAH: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 94.7% of the time and Tuesday flights 88.4%, against 83.9% for the route overall.
Set against the rest of the country, this route's record is 7 points better than the US average of 77.3%. That gap is worth roughly 66 fewer late arrivals for every thousand flights.
Key figures
On time
83.9%
Arrivals under 15 minutes late, of 1,677 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
0.30%
National rate is 1.89%
Best carrier
United
83.9% on time across 1,686 flights
These figures cover 1,686 flights between September 2025 and August 2026. The median arrival is 7 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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Carrier by carrier
Which airline is most reliable on SAN to IAH
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,686 | 83.9% | 70 min | 0.30% | B+ |
Flight by flight
Flights on SAN to IAH
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly San Diego to Houston
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 1 of the top 2 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SAN → IAHSan Diego to Houston | United Airlines | 83.6% | 83.9% | 0.30% | 5am–8am, Tue | UA 2237 11:58 |
| 2. SAN → HOUSan Diego to Houston | Southwest Airlines | 69.3% | 69.6% | 0.41% | 8am–11am, Sat | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 18 points, against half a point between the best and worst carrier.
- 5am–8am190 flights94.7%
- 8am–11am595 flights90.4%
- 11am–2pm421 flights76.7%
- 2pm–5pm303 flights77.4%
- 5pm–8pm177 flights78.5%
- 8pm–5am—
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 76.7% on time against 94.7% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8am–11am window is the busiest, with 595 flights scheduled in it.
Explore
Filter SAN to IAH by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SAN to IAH, the best departure window is 5am–8am at 94.7% on time and the worst is 11am–2pm at 76.7%, a wide gap of 18.0 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am94.7%
- 8–11am90.4%
- 11am–2pm76.7%
- 2–5pm77.4%
- 5–8pm78.5%
- 8pm–5am—
best all US flightsScale 60% to 100%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 21 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
August is the worst month at 71.5% on time, 21 points below February, the best at 92.1%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. March was the busiest month here, with 152 flights.
Across the week, Tuesday is the strongest day at 88.4% on time and Monday the weakest at 80.5%, a spread of 8 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 54% of the 19,000 delay minutes carriers reported here, and the remaining four split what is left.
- 54%Late-arriving aircraft
- 25%National Airspace System
- 17%Carrier
- 4%Extreme weather
54% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 19,000 reported delay minutes here, that single category outweighs weather by 12 to one. The split is drawn from 18,873 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 94.7% on time here.
Cancellations are rare at 0.30%, 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 stage length
What a delay here actually costs
5.2% 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 a little over 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 return leg runs 81.0% on time across 1,686 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,686 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in IAH after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 92.1% on time and August 71.5%, a swing of 21 points. If the dates move at all, move them out of August before you think about anything else. 1,677 completed flights over 12 months sit behind that.
Common questions
SAN to IAH questions
How often is SAN to IAH delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 16.1% of the 1,686 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
How reliable is SAN to IAH compared with the rest of the country?
83.9% of flights arrive on time here against a national 77.3%, a difference of 7 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on SAN to IAH?
The 5am–8am departure window is the strongest at 94.7% on time. The 11am–2pm window is the weakest at 76.7%, 18 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are August delays on SAN to IAH?
August is the weakest month at 71.5% on time, compared with 92.1% in February. Across the year that is 21 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- IAH to SAN — the return legseparate record
- San Diego International (SAN) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- SAN to SFO, a related route59.5%
- ORD to IAH, a related route76.0%
- SAN to DEN, a related route78.4%
- United Airlines on-time record83.9%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. SAN to IAH and IAH to SAN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.