Historical on-time performance
Washington to San Antonio
1,362 miData through Dec 2025Source: US DOT · BTS
Flights on IAD–SAT arrive on time 81% of the time over the last 12 months.
On-time rate81%arrived within 15 min
p90 delay40 min1 in 10 flights is worse (tail risk)
Cancelled0.3%of scheduled flights
based on 647 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- United AirlinesOn-time81%Medianon timep9040 minCancel0.3%Flights647
Why flights run late
Delay causes
- Airline25%
- Weather21%
- Air traffic (NAS)20%
- Late aircraft35%
- Security0%
Most delay minutes here are attributed to Late aircraft.
Over time
On-time trend
By season
On-time rate by month
When to fly
Best time to fly IAD → SAT
All airlines · rolling 36 months (2023-01 .. 2025-12).
Best time of day
Mornings are the most reliable time of day to fly this route — 89% on time.
- Mornings89% on time · p90 10 min · 890 flights
- Evenings76% on time · p90 60 min · 1,071 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 74% to 88% on time.
- Tuesdays88% on time · p90 20 min · 298 flights
- Mondays86% on time · p90 20 min · 311 flights
- Wednesdays82% on time · p90 30 min · 292 flights
- Fridays81% on time · p90 35 min · 311 flights
- Thursdays80% on time · p90 30 min · 307 flights
- Sundays78% on time · p90 60 min · 259 flights
- Saturdays74% on time · p90 60 min · 183 flights · limited
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