OnTimeStats

Historical on-time performance

Seattle to Boise

399 miData through May 2026Source: US DOT · BTS

Flights on SEA–BOI arrive on time 85% of the time over the last 12 months.

On-time rate85%arrived within 15 min
p90 delay20 min1 in 10 flights is worse (tail risk)
Cancelled0.3%of scheduled flights

based on 4,028 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • SkyWest Airlinesbest
    On-time86%
    Medianon time
    p9020 min
    Cancel0.2%
    Flights3,168
  • Alaska Airlines
    On-time79%
    Medianon time
    p9030 min
    Cancel0.5%
    Flights860

Why flights run late

Delay causes

  • Airline47%
  • Weather13%
  • Air traffic (NAS)14%
  • Late aircraft25%
  • Security1%

Most delay minutes here are attributed to Airline.

When flights don't go

Why flights were cancelled

  • Airline18%
  • Weather64%
  • Air traffic (NAS)18%
  • Security0%

Most cancellations here are attributed to Weather. Shares are among 11 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 SEA → BOI

All airlines · rolling 36 months (2023-06 .. 2026-05).

Best time of day

Mornings are the most reliable time of day to fly this route — 89% on time.

  • Mornings89% on time · p90 15 min · 1,997 flights
  • Afternoons85% on time · p90 20 min · 1,549 flights
  • Evenings83% on time · p90 25 min · 2,955 flights
  • Middays82% on time · p90 25 min · 3,688 flights
  • Overnights81% on time · p90 35 min · 1,761 flights

Best day of week

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

  • Tuesdays87% on time · p90 15 min · 1,662 flights
  • Saturdays87% on time · p90 20 min · 1,601 flights
  • Wednesdays86% on time · p90 20 min · 1,663 flights
  • Mondays83% on time · p90 25 min · 1,760 flights
  • Fridays82% on time · p90 25 min · 1,753 flights
  • Sundays82% on time · p90 30 min · 1,748 flights
  • Thursdays80% on time · p90 25 min · 1,763 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.