Historical on-time performance
Boston to San Antonio
1,764 miData through May 2026Source: US DOT · BTS
Flights on BOS–SAT arrive on time 83% of the time over the last 12 months.
On-time rate83%arrived within 15 min
p90 delay35 min1 in 10 flights is worse (tail risk)
Cancelled1.2%of scheduled flights
based on 242 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- Delta Air LinesOn-time83%Medianon timep9035 minCancel1.2%Flights242
Why flights run late
Delay causes
- Airline62%
- Weather0%
- Air traffic (NAS)9%
- Late aircraft28%
- Security0%
Most delay minutes here are attributed to Airline.
When flights don't go
Why flights were cancelled
- Airline100%
- Weather0%
- Air traffic (NAS)0%
- Security0%
Most cancellations here are attributed to Airline. Shares are among 3 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 BOS → SAT
All airlines · rolling 36 months (2023-06 .. 2026-05).
Best time of day
On-time rates are fairly even by time of day on this route — ranging from 77% to 78% on time.
- Middays78% on time · p90 35 min · 384 flights
- Mornings77% on time · p90 45 min · 614 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 72% to 80% on time.
- Wednesdays80% on time · p90 50 min · 148 flights · limited
- Mondays79% on time · p90 35 min · 154 flights · limited
- Thursdays79% on time · p90 25 min · 151 flights · limited
- Fridays77% on time · p90 35 min · 151 flights · limited
- Tuesdays76% on time · p90 55 min · 149 flights · limited
- Sundays75% on time · p90 60 min · 150 flights · limited
- Saturdays72% on time · p90 45 min · 132 flights · limited
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