Route profile
IAH→SAN
Flight reliability, delays and best times to fly from Houston to San Diego, 1,303 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 60% of comparable major US routes (4,598 compared)
Calculated from 5,436 flights. How this is calculated · What counts as on time
IAH → SAN arrives on time 80.3% of the time; the return trip, SAN → IAH, arrives on time 84.4% of the time, a 4.1-point gap between the two directions of the same city pair.
IAH → SAN spends 25.7 minutes on the ground on a 1,303-mile trip: 21.3 minutes from pushback to wheels-up at IAH and 4.3 minutes from touchdown to gate at SAN.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What sets this route apart
Where IAH to SAN differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
IAH to SAN is at its best against routes of similar length for flights scheduled at 4 PM: 81.6% arrive on time, 11.8 points ahead of the 69.8% those routes manage at that hour. Against all other routes the gap is 10.9 points.
IAH to SAN holds up on Sundays better than routes of similar length do: 79.2% on time to their 74.6%, a 4.6 points lead. Against all other routes the gap is 4.4 points.
March is kinder to IAH to SAN than to routes of similar length: 85.3% on time against 77.1%, 8.2 points better. Against all other routes the gap is 7.4 points.
IAH to SAN against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 4 PM departures | 81.6% | routes of similar length | 69.8% | +11.8 pts | 732 here, 108,426 there |
| Weekday: Sunday | 79.2% | routes of similar length | 74.6% | +4.6 pts | 792 here, 254,323 there |
| Month: March | 85.3% | routes of similar length | 77.1% | +8.2 pts | 430 here, 150,584 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 1,303 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
Why IAH → SAN flights are cancelled
July 2023 – July 2026
IAH → SAN cancelled 66 of 5,436 scheduled flights — about 1 in every 82. The reason filed most often was the airline, 45.5% of the cancellations coded on this route — about 1 in every 181 scheduled flights.
Share of cancellations
Of 66 cancelled departures carrying a reason code.
What each reason means
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
30 cancellations, 45.5% of the total.
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
27 cancellations, 40.9% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
9 cancellations, 13.6% of the total.
A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.
0 cancellations, 0.0% of the total.
Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. With only one or two carriers on the route, the split mostly reflects how they file. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.
66 coded cancellations were recorded on IAH → SAN; the section appears from 50.
When it goes wrong
July 2023 – July 2026
42 min late
against a median of 6 min early
Percentiles over 5,436 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SAN after arriving from IAH.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 35% | Likely to miss |
| 45 min | 19% | High risk |
| 60 min | 13% | Some risk |
| 90 min | 6.5% | Some risk |
| 120 min | 4.0% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 1.21% of the time and diverts 0.22% of the time, which a late arrival never shows up in.
Chance of missing is the share of 5,358 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 42 minutes late (90th-percentile gate arrival delay), over 5,436 operations.
Any other layover length: connection checker.
Best time to fly
IAH → SAN flights departing 5–9 AM arrived on time 87.9% of the time, against 74.1% for 6–9 PM departures, a gap of 13.8 percentage points.
By departure window
By departure hour
- 12 AM to 6 AM: too few flights to score
- 7 AM: 90.9% on time from 306 flights
- 8 AM: too few flights to score
- 9 AM: 85.6% on time from 1,091 flights
- 10 AM: too few flights to score
- 11 AM: 84.7% on time from 138 flights
- 12 PM: 81.8% on time from 664 flights
- 1 PM: too few flights to score
- 2 PM: 83.2% on time from 391 flights
- 3 PM: too few flights to score
- 4 PM: 81.6% on time from 735 flights
- 5 PM: too few flights to score
- 6 PM: 76.0% on time from 778 flights
- 7 PM: 65.5% on time from 341 flights
- 8 PM: 75.9% on time from 784 flights
- 9 PM to 11 PM: too few flights to score
Departure windows with fewer than 120 flights are not scored.
Why IAH → SAN runs late
July 2023 – July 2026
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for IAH → SAN. Only delays of 15 minutes or more are attributed. What the five causes mean
Late-arriving aircraft is the largest cause on IAH → SAN, at 38.3%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 87.9% of the time and 6–9 PM departures 74.1%.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| United Airlines | 5,319 | 80.3% | 1.17% | -6 min | 6.7% |
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| UA2491 United Airlines | 9:30 AM | 620 | 85.8% |
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Thursday the least, a gap of 7.8 percentage points.
By month
- Jan: 84.8%
- Feb: 86.5%
- Mar: 85.3%
- Apr: 81.8%
- May: 72.6%
- Jun: 69.4%
- Jul: 69.4%
- Aug: 82.6%
- Sep: 87.0%
- Oct: 82.6%
- Nov: 84.1%
- Dec: 84.4%
July is historically the weakest month and September the strongest, a spread of 17.6 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 79.3% from 152 flights
- August 2023: 85.2% from 155 flights
- September 2023: 86.9% from 168 flights
- October 2023: 84.7% from 183 flights
- November 2023: 83.4% from 145 flights
- December 2023: 92.6% from 148 flights
- January 2024: 84.0% from 131 flights
- February 2024: too few flights to score (113)
- March 2024: 83.3% from 138 flights
- April 2024: 80.9% from 141 flights
- May 2024: 66.3% from 173 flights
- June 2024: 74.9% from 180 flights
- July 2024: 60.8% from 185 flights
- August 2024: 86.2% from 181 flights
- September 2024: 85.3% from 143 flights
- October 2024: 77.6% from 147 flights
- November 2024: 89.2% from 148 flights
- December 2024: 77.6% from 148 flights
- January 2025: 86.9% from 129 flights
- February 2025: 82.8% from 122 flights
- March 2025: 85.9% from 142 flights
- April 2025: 83.0% from 141 flights
- May 2025: 69.7% from 145 flights
- June 2025: 60.7% from 141 flights
- July 2025: 68.1% from 141 flights
- August 2025: 75.0% from 141 flights
- September 2025: 89.0% from 137 flights
- October 2025: 84.9% from 147 flights
- November 2025: 79.6% from 142 flights
- December 2025: 82.6% from 145 flights
- January 2026: 83.5% from 128 flights
- February 2026: 91.3% from 127 flights
- March 2026: 86.7% from 152 flights
- April 2026: 81.7% from 142 flights
- May 2026: 82.6% from 149 flights
- June 2026: 71.1% from 142 flights
- July 2026: 70.4% from 144 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 81.4% against 79.5% in the 12 months before — improving by 1.9 percentage points.
Data and methodology
Calculated by FlyerIntel from 5,436 IAH → SAN flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed