OnTimeStats

Historical on-time performance

Chicago to Boston

867 miData through May 2026Source: US DOT · BTS

Flights on ORD–BOS arrive on time 66% of the time over the last 12 months.

On-time rate66%arrived within 15 min
p90 delay80 min1 in 10 flights is worse (tail risk)
Cancelled2.6%of scheduled flights

based on 7,460 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • Envoy Airbest
    On-time80%
    Medianon time
    p9040 min
    Cancel2.3%
    Flights430
  • JetBlue Airways
    On-time72%
    Medianon time
    p9070 min
    Cancel2.2%
    Flights508
  • Republic Airways
    On-time67%
    Medianon time
    p9060 min
    Cancel5.8%
    Flights828
  • United Airlines
    On-time67%
    Medianon time
    p9080 min
    Cancel1.7%
    Flights2,633
  • Delta Air Lines
    On-time67%
    Medianon time
    p9085 min
    Cancel2.4%
    Flights961
  • American Airlines
    On-time59%
    Medianon time
    p9090 min
    Cancel2.6%
    Flights2,100

Why flights run late

Delay causes

  • Airline20%
  • Weather5%
  • Air traffic (NAS)33%
  • Late aircraft41%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

When flights don't go

Why flights were cancelled

  • Airline12%
  • Weather66%
  • Air traffic (NAS)21%
  • Security0%

Most cancellations here are attributed to Weather. Shares are among 193 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 ORD → BOS

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 — 85% on time.

  • Mornings85% on time · p90 25 min · 6,931 flights
  • Middays70% on time · p90 70 min · 5,333 flights
  • Evenings63% on time · p90 85 min · 3,922 flights
  • Afternoons60% on time · p90 100 min · 2,613 flights
  • Overnights59% on time · p90 90 min · 2,084 flights

Best day of week

Saturdays are the most reliable day to fly this route — 78% on time.

  • Saturdays78% on time · p90 45 min · 2,550 flights
  • Tuesdays74% on time · p90 55 min · 2,872 flights
  • Wednesdays74% on time · p90 60 min · 2,906 flights
  • Mondays69% on time · p90 70 min · 3,161 flights
  • Thursdays69% on time · p90 75 min · 3,145 flights
  • Sundays69% on time · p90 75 min · 3,092 flights
  • Fridays67% on time · p90 75 min · 3,160 flights

Keep exploring

Related pages

Delay predictorfor this route→ORD airportChicago→BOS airportBoston→United Airlinesairline profile→American Airlinesairline profile→Delta Air Linesairline profile→Seasonal delay patternsguide→

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.