OnTimeStats

Historical on-time performance

Buffalo to Chicago

468 miData through May 2026Source: US DOT · BTS

Flights on BUF–MDW arrive on time 77% of the time over the last 12 months.

On-time rate77%arrived within 15 min
p90 delay40 min1 in 10 flights is worse (tail risk)
Cancelled1.2%of scheduled flights

based on 829 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).

By airline

How each carrier compares

  • Southwest Airlines
    On-time77%
    Medianon time
    p9040 min
    Cancel1.2%
    Flights829

Why flights run late

Delay causes

  • Airline21%
  • Weather0%
  • Air traffic (NAS)28%
  • Late aircraft50%
  • Security0%

Most delay minutes here are attributed to Late aircraft.

When flights don't go

Why flights were cancelled

  • Airline30%
  • Weather70%
  • Air traffic (NAS)0%
  • Security0%

Most cancellations here are attributed to Weather. Shares are among 10 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 BUF → MDW

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 — 90% on time.

  • Mornings90% on time · p90 10 min · 1,011 flights
  • Middays82% on time · p90 25 min · 299 flights
  • Evenings77% on time · p90 40 min · 498 flights
  • Afternoons74% on time · p90 45 min · 227 flights
  • Overnights61% on time · p90 65 min · 354 flights

Best day of week

On-time rates are fairly even by day on this route — ranging from 74% to 87% on time.

  • Tuesdays87% on time · p90 20 min · 360 flights
  • Wednesdays85% on time · p90 25 min · 360 flights
  • Mondays80% on time · p90 30 min · 377 flights
  • Thursdays78% on time · p90 30 min · 385 flights
  • Fridays78% on time · p90 40 min · 386 flights
  • Saturdays77% on time · p90 30 min · 216 flights
  • Sundays74% on time · p90 40 min · 305 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.