OnTimeStats

Historical on-time performance

Salt Lake City to Washington

1,827 miData through Dec 2025Source: US DOT · BTS

Flights on SLC–IAD arrive on time 85% of the time over the last 12 months.

On-time rate85%arrived within 15 min
p90 delay25 min1 in 10 flights is worse (tail risk)
Cancelled0.7%of scheduled flights

based on 584 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-time81%
    Medianon time
    p9040 min
    Cancel0.3%
    Flights308
  • United Airlinesbest
    On-time89%
    Medianon time
    p9015 min
    Cancel1.1%
    Flights276

Why flights run late

Delay causes

  • Airline55%
  • Weather3%
  • Air traffic (NAS)21%
  • Late aircraft22%
  • 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 SLC → IAD

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 82% to 88% on time.

  • Overnights88% on time · p90 15 min · 146 flights · limited
  • Mornings88% on time · p90 15 min · 89 flights · limited
  • Middays86% on time · p90 25 min · 133 flights · limited
  • Evenings82% on time · p90 35 min · 1,080 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 80% to 87% on time.

  • Saturdays87% on time · p90 20 min · 209 flights
  • Tuesdays87% on time · p90 40 min · 208 flights
  • Mondays85% on time · p90 30 min · 209 flights
  • Wednesdays84% on time · p90 30 min · 207 flights
  • Fridays83% on time · p90 30 min · 208 flights
  • Sundays80% on time · p90 35 min · 209 flights
  • Thursdays80% on time · p90 35 min · 207 flights
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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.