Route reliability record
HOU→SAN
Houston to San Diego
- Flights
- 961
- Period
- July 2025 to June 2026
- Distance
- 1,313 mi
- Carriers
- 1
This route lands a B+, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about 45 minutes on average. That is a workable record, not a spotless one. That rests on 961 HOU to SAN flights, with a median arrival 3 minutes early.
Best time to fly HOU to SAN: a 8am–11am departure, ideally on a Monday. Flights in that window arrived on time 90.7% of the time and Monday flights 79.9%, against 76.3% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.3%
Arrivals under 15 minutes late, of 951 completed flights
Avg delay
45 min
Across delayed arrivals only, not all flights
Cancelled
0.73%
National rate is 1.81%
Best carrier
Southwest
76.3% on time across 961 flights
These figures cover 961 flights between July 2025 and June 2026. The median arrival is 3 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.
Carrier by carrier
Which airline is most reliable on HOU to SAN
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 |
|---|---|---|---|---|---|
| Southwest Airlines | 961 | 76.3% | 45 min | 0.73% | B+ |
Best ways to make this trip
The most reliable ways to fly Houston to San Diego
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. IAH → SANHouston to San Diego | United Airlines | 81.0% | 81.3% | 0.41% | 8am–11am, Wed | UA 2491 09:30 |
| 2. HOU → SANHouston to San Diego | Southwest Airlines | 75.7% | 76.3% | 0.73% | 8am–11am, Mon | — |
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 34 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am84 flights90.4%
- 8am–11am282 flights90.7%
- 11am–2pm135 flights75.9%
- 2pm–5pm110 flights56.4%
- 5pm–8pm212 flights71.3%
- 8pm–5am138 flights62.8%
Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 90.7% of the time, against 56.4% for the afternoon window. That is 34 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 282 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 35 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.
June is the worst month at 59.3% on time, 35 points below August, the best at 93.8%. 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. December was the busiest month here, with 91 flights.
Across the week, Monday is the strongest day at 79.9% on time and Sunday the weakest at 72.5%. 7 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
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 10,000 reported delay minutes.
- 42%Late-arriving aircraft
- 36%Carrier
- 18%National Airspace System
- 4%Extreme weather
- 0%Security
42% 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 10,000 reported delay minutes here, that single category outweighs weather by 10 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 10,215 reported delay minutes.
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 3,685 of the 10,000 delay minutes reported here.
Cancellations are rare at 0.73%, 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 stage length
What a delay here actually costs
6.0% 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 45 minutes, which a normal layover absorbs.
The 1,313 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 return leg is a different operation and performs like one: it runs 71.4% on time across 961 flights, 5 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 5 points of difference.
One caution: this is a thin sample. 961 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.
Work out the risk of missing a connection in SAN after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 961 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 76.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 951 completed flights over 12 months sit behind that.
Common questions
HOU to SAN questions
How often is HOU to SAN delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.7% of the 961 flights in this analysis, against 22.4% nationally. Delayed flights are late by about 45 minutes on average.
How reliable is HOU to SAN compared with the rest of the country?
76.3% of flights arrive on time here against a national 77.6%, a difference of about a point against it. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on HOU to SAN?
The 8am–11am departure window is the strongest at 90.7% on time. The 2pm–5pm window is the weakest at 56.4%, 34 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 June delays on HOU to SAN?
June is the weakest month at 59.3% on time, compared with 93.8% in August. Across the year that is 35 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
- SAN to HOU — the return legseparate record
- William P. Hobby (HOU) delay statistics
- San Diego International (SAN) delay statistics
- HOU to DAL, a related route80.9%
- SFO to SAN, a related route66.6%
- HOU to ATL, a related route79.8%
- Southwest Airlines on-time record76.3%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. HOU to SAN and SAN to HOU 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.