Historical on-time performance
Chicago to Boston
861 miData through May 2026Source: US DOT · BTS
Flights on MDW–BOS arrive on time 67% of the time over the last 12 months.
On-time rate67%arrived within 15 min
p90 delay60 min1 in 10 flights is worse (tail risk)
Cancelled1.1%of scheduled flights
based on 1,395 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- Southwest AirlinesOn-time67%Medianon timep9060 minCancel1.1%Flights1,395
Why flights run late
Delay causes
- Airline29%
- Weather2%
- Air traffic (NAS)36%
- Late aircraft31%
- Security1%
Most delay minutes here are attributed to Air traffic (NAS).
When flights don't go
Why flights were cancelled
- Airline0%
- Weather87%
- Air traffic (NAS)13%
- Security0%
Most cancellations here are attributed to Weather. Shares are among 15 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 MDW → 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 — 90% on time.
- Mornings90% on time · p90 10 min · 1,392 flights
- Middays69% on time · p90 60 min · 738 flights
- Evenings63% on time · p90 65 min · 856 flights
- Overnights57% on time · p90 80 min · 419 flights
- Afternoons55% on time · p90 90 min · 674 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 65% to 79% on time.
- Saturdays79% on time · p90 30 min · 518 flights
- Tuesdays76% on time · p90 45 min · 540 flights
- Wednesdays75% on time · p90 40 min · 535 flights
- Fridays70% on time · p90 60 min · 629 flights
- Mondays69% on time · p90 55 min · 616 flights
- Thursdays67% on time · p90 70 min · 625 flights
- Sundays65% on time · p90 65 min · 616 flights
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