OnTimeStats

Historical on-time performance

St. Thomas to Washington

1,606 miData through May 2026Source: US DOT · BTS

Flights on STT–IAD arrive on time 82% of the time over the last 12 months.

On-time rate82%arrived within 15 min
p90 delay35 min1 in 10 flights is worse (tail risk)
Cancelled1.5%of scheduled flights

based on 266 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • United Airlines
    On-time82%
    Medianon time
    p9035 min
    Cancel1.5%
    Flights266

Why flights run late

Delay causes

  • Airline27%
  • Weather0%
  • Air traffic (NAS)17%
  • Late aircraft56%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

When flights don't go

Why flights were cancelled

  • Airline0%
  • Weather25%
  • Air traffic (NAS)75%
  • Security0%

Most cancellations here are attributed to Air traffic (NAS). Shares are among 4 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 STT → IAD

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 78% to 83% on time.

  • Middays83% on time · p90 25 min · 481 flights
  • Afternoons78% on time · p90 40 min · 446 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 78% to 85% on time.

  • Mondays85% on time · p90 30 min · 129 flights · limited
  • Sundays83% on time · p90 25 min · 135 flights · limited
  • Tuesdays81% on time · p90 30 min · 127 flights · limited
  • Saturdays81% on time · p90 30 min · 172 flights · limited
  • Wednesdays80% on time · p90 50 min · 127 flights · limited
  • Fridays78% on time · p90 45 min · 129 flights · limited
  • Thursdays78% on time · p90 55 min · 128 flights · limited

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.