Route reliability record
HOU→SAN
Houston to San Diego
- Flights
- 985
- Period
- September 2025 to August 2026
- Distance
- 1,313 mi
- Carriers
- 1
This route sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land about 45 minutes behind schedule. That rests on 985 HOU to SAN flights, with a median arrival 1 minute early.
Best time to fly HOU to SAN: a 8am–11am departure, ideally on a Monday. Flights in that window arrived on time 90.0% of the time and Monday flights 78.7%, against 73.9% for the route overall.
The US average over the same twelve months is 77.3%, 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
73.9%
Arrivals under 15 minutes late, of 974 completed flights
Avg delay
45 min
Across delayed arrivals only, not all flights
Cancelled
0.71%
National rate is 1.89%
Best carrier
Southwest
73.9% on time across 985 flights
These figures cover 985 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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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 | 985 | 73.9% | 45 min | 0.71% | C+ |
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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 | 80.9% | 81.0% | 0.18% | 2pm–5pm, Tue | UA 2491 09:30 |
| 2. HOU → SANHouston to San Diego | Southwest Airlines | 73.4% | 73.9% | 0.71% | 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 33 points, against half a point between the best and worst carrier.
- 5am–8am92 flights89.0%
- 8am–11am274 flights90.0%
- 11am–2pm166 flights70.1%
- 2pm–5pm98 flights57.1%
- 5pm–8pm227 flights67.0%
- 8pm–5am128 flights59.1%
Scale runs 50% to 95%.
Book the morning departure. Flights leaving between 8am–11am arrive on time 90.0% of the time, against 57.1% for the afternoon window. That is 33 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 274 flights scheduled in it.
Explore
Filter HOU to SAN 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 HOU to SAN, the best departure window is 8am–11am at 90.0% on time and the worst is 2pm–5pm at 57.1%, a wide gap of 32.9 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am89.0%
- 8–11am90.0%
- 11am–2pm70.1%
- 2–5pm57.1%
- 5–8pm67.0%
- 8pm–5am59.1%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 31 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, 31 points below February, the best at 90.1%. 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. December was the busiest month here, with 91 flights.
Across the week, Monday is the strongest day at 78.7% on time and Sunday the weakest at 68.3%, a spread of 10 points.
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 11,000 reported delay minutes.
- 39%Late-arriving aircraft
- 33%Carrier
- 22%National Airspace System
- 6%Extreme weather
- 0%Security
39% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 7 to one. The split is drawn from 11,486 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 90.0% on time here.
Cancellations are rare at 0.71%, 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
6.7% 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 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.
The return leg is a different operation and performs like one: it runs 69.6% on time across 985 flights, 4 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 4 points of difference.
One caution: this is a thin sample. 985 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. 985 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 73.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 974 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 26.1% of the 985 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 45 minutes on average.
How reliable is HOU to SAN compared with the rest of the country?
73.9% of flights arrive on time here against a national 77.3%, a difference of 3 points against it. That is worth a C+ 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 90.0% on time. The 2pm–5pm window is the weakest at 57.1%, 33 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 90.1% in February. Across the year that is 31 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 route81.6%
- SFO to SAN, a related route62.2%
- HOU to ATL, a related route79.2%
- Southwest Airlines on-time record73.9%
- 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. 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.