OnTimeStats

Historical on-time performance

Chicago to San Juan

2,072 miData through Dec 2025Source: US DOT · BTS

Flights on ORD–SJU arrive on time 78% of the time over the last 12 months.

On-time rate78%arrived within 15 min
p90 delay40 min1 in 10 flights is worse (tail risk)
Cancelled0.2%of scheduled flights

based on 1,108 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

Too close to call — no single carrier is clearly more on-time here.

  • United Airlines
    On-time79%
    Medianon time
    p9035 min
    Cancel0.0%
    Flights624
  • American Airlines
    On-time79%
    Medianon time
    p9035 min
    Cancel0.0%
    Flights253
  • Spirit Airlines
    On-time75%
    Medianon time
    p9050 min
    Cancel0.9%
    Flights231

Why flights run late

Delay causes

  • Airline37%
  • Weather7%
  • Air traffic (NAS)32%
  • Late aircraft24%
  • Security0%

Most delay minutes here are attributed to Airline.

Over time

On-time trend

By season

On-time rate by month

When to fly

Best time to fly ORD → SJU

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 65% to 81% on time.

  • Afternoons81% on time · p90 30 min · 358 flights
  • Mornings80% on time · p90 35 min · 2,300 flights
  • Middays80% on time · p90 40 min · 334 flights
  • Overnights77% on time · p90 45 min · 133 flights · limited
  • Evenings65% on time · p90 60 min · 303 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 75% to 84% on time.

  • Tuesdays84% on time · p90 25 min · 451 flights
  • Mondays81% on time · p90 35 min · 495 flights
  • Thursdays80% on time · p90 30 min · 483 flights
  • Saturdays78% on time · p90 40 min · 552 flights
  • Wednesdays78% on time · p90 40 min · 440 flights
  • Sundays75% on time · p90 45 min · 487 flights
  • Fridays75% on time · p90 40 min · 520 flights
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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.