OnTimeStats

Historical on-time performance

Salt Lake City to Washington

1,828 miData through May 2026Source: 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)
Cancelled1.0%of scheduled flights

based on 614 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • United Airlinesbest
    On-time89%
    Medianon time
    p9015 min
    Cancel0.7%
    Flights306
  • Delta Air Lines
    On-time81%
    Medianon time
    p9035 min
    Cancel1.3%
    Flights308

Why flights run late

Delay causes

  • Airline56%
  • Weather5%
  • Air traffic (NAS)21%
  • Late aircraft19%
  • Security0%

Most delay minutes here are attributed to Airline.

When flights don't go

Why flights were cancelled

  • Airline33%
  • Weather67%
  • Air traffic (NAS)0%
  • Security0%

Most cancellations here are attributed to Weather. Shares are among 6 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 SLC → 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 83% to 89% on time.

  • Mornings89% on time · p90 10 min · 113 flights · limited
  • Overnights88% on time · p90 15 min · 186 flights · limited
  • Middays85% on time · p90 25 min · 220 flights
  • Evenings83% on time · p90 35 min · 1,089 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 81% to 87% on time.

  • Tuesdays87% on time · p90 25 min · 228 flights
  • Saturdays87% on time · p90 20 min · 232 flights
  • Mondays85% on time · p90 30 min · 229 flights
  • Wednesdays84% on time · p90 25 min · 227 flights
  • Fridays84% on time · p90 50 min · 231 flights
  • Thursdays82% on time · p90 25 min · 230 flights
  • Sundays81% on time · p90 25 min · 231 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.