OnTimeStats

Historical on-time performance

San Antonio to Boston

1,764 miData through Dec 2025Source: US DOT · BTS

Flights on SAT–BOS arrive on time 49% of the time over the last 12 months.

On-time rate49%arrived within 15 min
p90 delay120 min1 in 10 flights is worse (tail risk)
Cancelled1.1%of scheduled flights

based on 181 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • Delta Air Lines
    On-time49%
    Median15 min
    p90120 min
    Cancel1.1%
    Flights181

Why flights run late

Delay causes

  • Airline7%
  • Weather11%
  • Air traffic (NAS)64%
  • Late aircraft19%
  • Security0%

Most delay minutes here are attributed to Air traffic (NAS).

Over time

On-time trend

By season

On-time rate by month

When to fly

Best time to fly SAT → BOS

All airlines · rolling 36 months (2023-01 .. 2025-12).

Best time of day

On-time rates are fairly even by time of day on this route — ranging from 62% to 66% on time.

  • Evenings66% on time · p90 75 min · 123 flights · limited
  • Afternoons65% on time · p90 80 min · 464 flights
  • Middays62% on time · p90 90 min · 450 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 57% to 70% on time.

  • Wednesdays70% on time · p90 115 min · 149 flights · limited
  • Saturdays67% on time · p90 80 min · 132 flights · limited
  • Tuesdays64% on time · p90 70 min · 150 flights · limited
  • Sundays64% on time · p90 80 min · 150 flights · limited
  • Mondays63% on time · p90 75 min · 155 flights · limited
  • Thursdays62% on time · p90 90 min · 151 flights · limited
  • Fridays57% on time · p90 95 min · 150 flights · limited
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Keep exploring

Related pages

Methodology

A flight is on time when it arrives within 15 minutes of schedule — the US DOT / BTS standard. Median and p90(the “1-in-10 bad day”) are read from the full arrival-delay distribution, never averaged across periods.

Figures cover a carrier’s own BTS-coded flights. Cells below ~200 flights are flagged as limited data. All numbers are pre-computed from public BTS On-Time Performance data.