(UA) United Airlines 4521 On-Time Performance Rating

Date Range:

15-Jul-2026 to 15-Sep-2026

(ROC) Frederick Douglass Greater Rochester Intl Airport

Rochester, NY, US

(IAD) Washington Dulles International Airport

Dulles, VA, US

On-Time Performance Chart

(using rounded numbers)

On-Time

81%

Late

Very Late

Excessive

13%

Cancelled

Diverted

Delay Statistics

(Aggregate Arrival Delay Statistics for this Flight)

Total Flights Observed

Total Delays ( > 1 min )

Codeshares

Average Delay (min.)

352

Standard Deviation

70.7

Min

Max

402

UA 4521 On-Time Performance Details

Overall Rating

2.0 of 5

Average

Percentage On-Time 81%

Average Delay Time 352 min

FlightStats Rating is a merit measurement considering both on-time performance and delay severity. The score, 2 shows that this flight has on-time performance characteristics better than 38% of all other flights in the FlightStats database.

On-Time Performance Rating

3.9 of 5

Good

Percentage On-Time 81%

This flight has an on-time performance of 81%. Statistically, when taking into consideration sample size, standard deviation, and mean, this flight is on-time more often than 79% of other flights.

Delay Performance

0.0 of 5

Very Poor

Average Delay Time 352 min

This flight has an average delay of 352 minutes with a standard deviation of 70.7 minutes. Statistically, when taking into consideration sample size, standard deviation, and mean, this flight has delay performance characteristics better than 0% of other flights.