OnTimeStats

Historical on-time performance

Miami to San Juan

1,045 miData through May 2026Source: US DOT · BTS

Flights on MIA–SJU arrive on time 74% of the time over the last 12 months.

On-time rate74%arrived within 15 min
p90 delay55 min1 in 10 flights is worse (tail risk)
Cancelled1.0%of scheduled flights

based on 2,359 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • American Airlinesbest
    On-time76%
    Medianon time
    p9050 min
    Cancel0.6%
    Flights2,048
  • Frontier Airlines
    On-time67%
    Medianon time
    p9085 min
    Cancel2.5%
    Flights280
  • Spirit Airlines
    On-time32%
    Median35 min
    p90185 min
    Cancel12.9%
    Flights31

Why flights run late

Delay causes

  • Airline41%
  • Weather3%
  • Air traffic (NAS)15%
  • Late aircraft40%
  • Security0%

Most delay minutes here are attributed to Airline.

When flights don't go

Why flights were cancelled

  • Airline29%
  • Weather42%
  • Air traffic (NAS)29%
  • Security0%

Most cancellations here are attributed to Weather. Shares are among 24 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 MIA → SJU

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 — 87% on time.

  • Mornings87% on time · p90 20 min · 2,567 flights
  • Middays73% on time · p90 50 min · 2,583 flights
  • Afternoons69% on time · p90 85 min · 1,346 flights
  • Evenings65% on time · p90 70 min · 1,174 flights
  • Overnights65% on time · p90 80 min · 546 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 70% to 80% on time.

  • Wednesdays80% on time · p90 35 min · 1,077 flights
  • Tuesdays78% on time · p90 45 min · 1,085 flights
  • Mondays77% on time · p90 50 min · 1,226 flights
  • Fridays75% on time · p90 55 min · 1,248 flights
  • Thursdays74% on time · p90 55 min · 1,218 flights
  • Saturdays70% on time · p90 65 min · 1,182 flights
  • Sundays70% on time · p90 65 min · 1,246 flights

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.