Route profile
IAH→SAT
Flight reliability, delays and best times to fly from Houston to San Antonio, 191 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 50% of comparable major US routes (4,598 compared)
Calculated from 6,990 flights. How this is calculated
IAH → SAT arrives on time 79.1% of the time; the return trip, SAT → IAH, arrives on time 83.2% of the time, a 4.1-point gap between the two directions of the same city pair.
IAH → SAT spends 25.0 minutes on the ground on a 191-mile trip: 21.2 minutes from pushback to wheels-up at IAH and 3.8 minutes from touchdown to gate at SAT.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Every airline on this route performs about the same, a narrower carrier gap than 99% of 2,692 comparable routes.
United Airlines (79.1% on time) and SkyWest Airlines (78.9%) are close together here.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 2,692 in the comparison.
Why IAH → SAT flights are cancelled
July 2023 – July 2026
IAH → SAT cancelled 93 of 6,990 scheduled flights — about 1 in every 75. The reason filed most often was extreme weather, 53.8% of the cancellations coded on this route — about 1 in every 140 scheduled flights.
Share of cancellations
Of 93 cancelled departures carrying a reason code.
What each reason means
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
50 cancellations, 53.8% of the total.
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
32 cancellations, 34.4% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
11 cancellations, 11.8% 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.
93 coded cancellations were recorded on IAH → SAT; the section appears from 50.
When it goes wrong
July 2023 – July 2026
46 min late
against a median of 6 min early
Percentiles over 6,990 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at SAT after arriving from IAH.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 36% | Likely to miss |
| 45 min | 20% | High risk |
| 60 min | 14% | Some risk |
| 90 min | 7.3% | Some risk |
| 120 min | 4.4% | 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 1.33% of the time and diverts 0.09% of the time, which a late arrival never shows up in.
Chance of missing is the share of 6,891 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 46 minutes late (90th-percentile gate arrival delay), over 6,990 operations.
Any other layover length: connection checker.
Best time to fly
IAH → SAT flights departing 5–9 AM arrived on time 92.6% of the time, against 72.0% for 3–6 PM departures, a gap of 20.6 percentage points.
By departure window
By departure hour
- 12 AM to 6 AM: too few flights to score
- 7 AM: 92.6% on time from 1,013 flights
- 8 AM: too few flights to score
- 9 AM: 82.5% on time from 403 flights
- 10 AM: 84.0% on time from 325 flights
- 11 AM: 89.8% on time from 158 flights
- 12 PM: 82.7% on time from 503 flights
- 1 PM: too few flights to score
- 2 PM: 79.7% on time from 802 flights
- 3 PM: too few flights to score
- 4 PM: 74.0% on time from 687 flights
- 5 PM: too few flights to score
- 6 PM: 73.8% on time from 1,069 flights
- 7 PM: 59.1% on time from 241 flights
- 8 PM: 75.2% on time from 865 flights
- 9 PM: 75.9% on time from 665 flights
- 10 PM: 82.5% on time from 205 flights
- 11 PM: too few flights to score
Why IAH → SAT 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 → SAT. Only delays of 15 minutes or more are attributed.
Late-arriving aircraft is the largest cause on IAH → SAT, at 44.4%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 92.6% of the time and 3–6 PM departures 72.0%.
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 | 6,485 | 79.1% | 1.33% | -6 min | 7.6% |
| SkyWest Airlines | 505 | 78.9% | 1.39% | -6 min | 8.4% |
United Airlines flew 92.8% of the 6,990 flights listed.
Carriers on this route performed within a couple of percentage points of each other.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Friday the least, a gap of 6.3 percentage points.
By month
- Jan: 81.5%
- Feb: 84.7%
- Mar: 79.9%
- Apr: 81.0%
- May: 75.0%
- Jun: 70.0%
- Jul: 67.9%
- Aug: 79.2%
- Sep: 82.8%
- Oct: 83.2%
- Nov: 84.8%
- Dec: 82.1%
July is historically the weakest month and November the strongest, a spread of 16.9 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 71.6% from 209 flights
- August 2023: 84.5% from 215 flights
- September 2023: 78.4% from 205 flights
- October 2023: 79.0% from 200 flights
- November 2023: 86.4% from 148 flights
- December 2023: 88.8% from 152 flights
- January 2024: 72.7% from 158 flights
- February 2024: 83.8% from 130 flights
- March 2024: too few flights to score (114)
- April 2024: 76.0% from 151 flights
- May 2024: 59.3% from 145 flights
- June 2024: 68.4% from 139 flights
- July 2024: 54.6% from 200 flights
- August 2024: 74.4% from 218 flights
- September 2024: 82.2% from 230 flights
- October 2024: 84.6% from 234 flights
- November 2024: 85.1% from 222 flights
- December 2024: 74.2% from 182 flights
- January 2025: 79.5% from 176 flights
- February 2025: 79.3% from 188 flights
- March 2025: 80.9% from 230 flights
- April 2025: 83.7% from 142 flights
- May 2025: 80.1% from 199 flights
- June 2025: 71.9% from 212 flights
- July 2025: 71.6% from 185 flights
- August 2025: 78.7% from 208 flights
- September 2025: 87.3% from 229 flights
- October 2025: 85.4% from 213 flights
- November 2025: 83.4% from 207 flights
- December 2025: 83.9% from 217 flights
- January 2026: 90.4% from 179 flights
- February 2026: 91.6% from 168 flights
- March 2026: 82.1% from 234 flights
- April 2026: 82.8% from 215 flights
- May 2026: 81.6% from 185 flights
- June 2026: 69.0% from 171 flights
- July 2026: 73.3% from 180 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 82.6% against 79.0% in the 12 months before — improving by 3.6 percentage points.
Data and methodology
Calculated by FlyerIntel from 6,990 IAH → SAT 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