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Flight Reliability

UA 4877 · United Airlines

Washington → Rochester (IAD–ROC)94% of its flights flew this route. The rest (ORF–IAD, IAH–BRO) are included in these numbers.

74
Usually Fine
WanderNerd Reliability Score
84%
Arrive within 15 minutes
18 min
Average arrival delay
2.7%
Cancelled
5 min early
Median arrival delay

Based on 148 historical flights. Data through May 2026.

What the data says

Saturdays have been rough.

UA 4877 arrived on time 96% of the time on Fridays and just 77% on Saturdays. That gap is worth planning around.

A bit ahead of the IAD–ROC route.

UA 4877 arrived on time 84% of the time, versus 78% across the IAD–ROC route.

A bit ahead of the United Airlines network.

UA 4877 arrived on time 84% of the time, versus 79% across the United Airlines network.

The breakdown

On-time by weekday
  • Mon80%(20 flights)
  • Tue80%(15 flights)
  • Wed90%(20 flights)
  • Thu82%(22 flights)
  • Fri96%(24 flights)
  • Sat77%(17 flights)
  • Sun80%(25 flights)
On-time by departure window
  • 6–9 AM87%(134 flights)
  • 12–3 PM—(7 flights)
  • 9 PM–12 AM—(2 flights)
On-time trend by month
90%
Apr

Jun 50% → Apr 90% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202550%10
July 202582%27
August 2025100%15
December 202577%13
January 202688%16
February 202691%23
March 202685%27
April 202690%10
Departures on time
88%
Diverted
0.7%
Flights flown
143
Months covered
9

Same route, other flights

Keep nerding

Based on 148 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.