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Flight Reliability

UA 4327 · United Airlines

Washington → Dayton (IAD–DAY)85% of its flights flew this route. The rest (IAD–BUF, IAD–GSP) are included in these numbers.

89
Pretty Reliable
WanderNerd Reliability Score
87%
Arrive within 15 minutes
0 min
Average arrival delay
1.4%
Cancelled
9 min early
Median arrival delay

Based on 213 historical flights. Data through May 2026.

What the data says

Sunday scaries are real for this one.

UA 4327 arrived on time 95% of the time on Thursdays. On Sundays: 83%.

A bit ahead of the IAD–DAY route.

UA 4327 arrived on time 87% of the time, versus 82% across the IAD–DAY route.

Better than the United Airlines network average.

UA 4327 arrived on time 87% of the time, versus 79% across the United Airlines network.

Ticking up lately.

UA 4327 arrived on time 91% of the time over the last three months in the data, compared with 86% in the three months before that.

The breakdown

On-time by weekday
  • Mon84%(31 flights)
  • Tue83%(24 flights)
  • Wed86%(21 flights)
  • Thu95%(21 flights)
  • Fri87%(30 flights)
  • Sat89%(47 flights)
  • Sun83%(36 flights)
On-time by departure window
  • 6–9 AM87%(190 flights)
  • 3–6 PM86%(14 flights)
  • 6–9 PM—(6 flights)
On-time trend by month
93%
May

Jun 76% → May 93% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202576%21
July 202587%31
August 202582%28
September 202587%30
October 202589%26
November 202591%11
April 202688%17
May 202693%30
Departures on time
89%
Diverted
0%
Flights flown
210
Months covered
12

Same route, other flights

Keep nerding

Based on 213 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.