OnTimeStats

Historical on-time performance

San Juan to Detroit

1,929 miData through Dec 2025Source: US DOT · BTS

Flights on SJU–DTW arrive on time 82% of the time over the last 12 months.

On-time rate82%arrived within 15 min
p90 delay40 min1 in 10 flights is worse (tail risk)
Cancelled0.4%of scheduled flights

based on 274 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-time82%
    Medianon time
    p9040 min
    Cancel0.4%
    Flights274

Why flights run late

Delay causes

  • Airline35%
  • Weather2%
  • Air traffic (NAS)20%
  • Late aircraft43%
  • 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 SJU → DTW

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

Best time of day

Middays are the most reliable time of day to fly this route — 90% on time.

  • Middays90% on time · p90 10 min · 148 flights · limited
  • Afternoons80% on time · p90 35 min · 915 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 75% to 87% on time.

  • Tuesdays87% on time · p90 15 min · 138 flights · limited
  • Wednesdays85% on time · p90 15 min · 146 flights · limited
  • Mondays83% on time · p90 35 min · 172 flights · limited
  • Saturdays81% on time · p90 35 min · 215 flights
  • Thursdays81% on time · p90 45 min · 150 flights · limited
  • Sundays81% on time · p90 40 min · 154 flights · limited
  • Fridays75% on time · p90 45 min · 169 flights · limited
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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.