Historical on-time performance
Washington to Chicago
589 miData through May 2026Source: US DOT · BTS
Flights on IAD–ORD arrive on time 74% of the time over the last 12 months.
On-time rate74%arrived within 15 min
p90 delay45 min1 in 10 flights is worse (tail risk)
Cancelled0.8%of scheduled flights
based on 2,024 flights over the last 12 months. On-time means arriving within 15 minutes (BTS standard).
By airline
How each carrier compares
- United AirlinesOn-time74%Medianon timep9045 minCancel0.8%Flights2,024
Why flights run late
Delay causes
- Airline19%
- Weather9%
- Air traffic (NAS)53%
- Late aircraft19%
- Security0%
Most delay minutes here are attributed to Air traffic (NAS).
When flights don't go
Why flights were cancelled
- Airline19%
- Weather75%
- Air traffic (NAS)6%
- Security0%
Most cancellations here are attributed to Weather. Shares are among 16 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 IAD → ORD
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 — 87% on time.
- Mornings87% on time · p90 15 min · 1,834 flights
- Middays84% on time · p90 30 min · 1,186 flights
- Overnights79% on time · p90 40 min · 1,099 flights
- Afternoons64% on time · p90 90 min · 207 flights
- Evenings57% on time · p90 80 min · 1,162 flights
Best day of week
On-time rates are fairly even by day on this route — ranging from 76% to 80% on time.
- Tuesdays80% on time · p90 35 min · 784 flights
- Wednesdays79% on time · p90 35 min · 779 flights
- Sundays78% on time · p90 40 min · 785 flights
- Saturdays78% on time · p90 40 min · 782 flights
- Thursdays76% on time · p90 40 min · 783 flights
- Mondays76% on time · p90 40 min · 784 flights
- Fridays76% on time · p90 40 min · 791 flights
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