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Flight Reliability

UA 1233 · United Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and UA 1233 moved between routes during this period. Numbers below combine all of them, so treat them as background, not a verdict. For a cleaner answer, check the route you are actually flying.

Combined across all its routes

81%
Arrive within 15 minutes
4 min
Average arrival delay
1.8%
Cancelled
7 min early
Median arrival delay

Based on 657 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon82%(91 flights)
  • Tue89%(88 flights)
  • Wed83%(86 flights)
  • Thu76%(95 flights)
  • Fri80%(97 flights)
  • Sat82%(89 flights)
  • Sun73%(97 flights)
On-time by departure window
  • 6–9 AM92%(166 flights)
  • 9 AM–12 PM77%(362 flights)
  • 6–9 PM77%(115 flights)
On-time trend by month
93%
May

Jun 80% → May 93% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202580%35
July 202577%60
August 202571%61
September 202571%31
October 202571%35
November 202583%58
December 202581%62
January 202684%73
February 202688%67
March 202673%60
April 202690%59
May 202693%42
Departures on time
82%
Diverted
0.3%
Flights flown
643
Months covered
12

Keep nerding

Based on 657 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.