Historical on-time performance
Houston to San Antonio
191 miData through May 2026Source: US DOT · BTS
Flights on IAH–SAT arrive on time 82% of the time over the last 12 months.
On-time rate82%arrived within 15 min
p90 delay30 min1 in 10 flights is worse (tail risk)
Cancelled0.8%of scheduled flights
based on 2,363 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- United AirlinesOn-time82%Medianon timep9030 minCancel0.8%Flights2,363
Why flights run late
Delay causes
- Airline37%
- Weather8%
- Air traffic (NAS)11%
- Late aircraft43%
- Security0%
Most delay minutes here are attributed to Late aircraft.
When flights don't go
Why flights were cancelled
- Airline15%
- Weather75%
- Air traffic (NAS)10%
- Security0%
Most cancellations here are attributed to Weather. Shares are among 20 cancellations with a reported cause (BTS reports causes from June 2003).
Over time
On-time trend
By season
On-time rate by month
When to fly
Best time to fly IAH → SAT
All airlines · rolling 36 months (2023-06 .. 2026-05).
Best time of day
Mornings are the most reliable time of day to fly this route — 88% on time.
- Mornings88% on time · p90 15 min · 1,382 flights
- Middays83% on time · p90 30 min · 1,020 flights
- Afternoons77% on time · p90 45 min · 1,421 flights
- Overnights75% on time · p90 55 min · 1,675 flights
- Evenings69% on time · p90 65 min · 1,347 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 75% to 82% on time.
- Tuesdays82% on time · p90 35 min · 995 flights
- Saturdays81% on time · p90 35 min · 951 flights
- Wednesdays81% on time · p90 40 min · 981 flights
- Sundays77% on time · p90 55 min · 954 flights
- Thursdays76% on time · p90 50 min · 976 flights
- Fridays76% on time · p90 45 min · 996 flights
- Mondays75% on time · p90 50 min · 992 flights
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