Historical on-time performance
Washington to St. Thomas
1,606 miData through Dec 2025Source: US DOT · BTS
Flights on IAD–STT arrive on time 86% of the time over the last 12 months.
On-time rate86%arrived within 15 min
p90 delay20 min1 in 10 flights is worse (tail risk)
Cancelled0.0%of scheduled flights
based on 259 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- United AirlinesOn-time86%Medianon timep9020 minCancel0.0%Flights259
Why flights run late
Delay causes
- Airline33%
- Weather0%
- Air traffic (NAS)46%
- Late aircraft21%
- 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 IAD → STT
All airlines · rolling 36 months (2023-01 .. 2025-12).
Best day of week
On-time rates are fairly even by day on this route — ranging from 84% to 92% on time.
- Thursdays92% on time · p90 10 min · 123 flights · limited
- Tuesdays89% on time · p90 15 min · 124 flights · limited
- Fridays88% on time · p90 15 min · 123 flights · limited
- Saturdays88% on time · p90 15 min · 168 flights · limited
- Mondays87% on time · p90 15 min · 125 flights · limited
- Wednesdays87% on time · p90 15 min · 124 flights · limited
- Sundays84% on time · p90 15 min · 134 flights · limited
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