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WanderNerd

Flight Reliability

UA 4237 · United Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and UA 4237 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

86%
Arrive within 15 minutes
4 min
Average arrival delay
2.5%
Cancelled
12 min early
Median arrival delay

Based on 315 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon85%(47 flights)
  • Tue90%(38 flights)
  • Wed88%(42 flights)
  • Thu84%(45 flights)
  • Fri78%(49 flights)
  • Sat94%(35 flights)
  • Sun88%(51 flights)
On-time by departure window
  • 9 AM–12 PM91%(23 flights)
  • 12–3 PM(8 flights)
  • 3–6 PM88%(246 flights)
  • 6–9 PM70%(30 flights)
On-time trend by month
83%
May

Jun 85% → May 83% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202585%26
July 202573%15
August 202579%24
September 202590%30
October 202586%28
November 202589%18
December 202587%31
January 202697%30
February 202696%24
March 202682%28
April 202683%29
May 202683%24
Departures on time
86%
Diverted
0%
Flights flown
307
Months covered
12

Based on 315 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.