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Flight Reliability

UA 540 · United Airlines

Denver → San Diego (DEN–SAN)82% of its flights flew this route. The rest (BWI–DEN, PNS–DEN) are included in these numbers.

73
Usually Fine
WanderNerd Reliability Score
70%
Arrive within 15 minutes
13 min
Average arrival delay
0.5%
Cancelled
0 min
Median arrival delay

Based on 442 historical flights. Data through May 2026.

What the data says

The 12–3 PM departure wins.

UA 540 departing between 12–3 PM arrived on time 91% of the time, versus 67% between 6–9 PM.

Sunday scaries are real for this one.

UA 540 arrived on time 79% of the time on Wednesdays and just 61% on Sundays. That gap is worth planning around.

A bit behind the DEN–SAN route.

UA 540 arrived on time 70% of the time, versus 76% across the DEN–SAN route.

Lagging the United Airlines network.

UA 540 arrived on time 70% of the time, versus 79% across the United Airlines network.

The breakdown

On-time by weekday
  • Mon69%(62 flights)
  • Tue72%(60 flights)
  • Wed79%(61 flights)
  • Thu65%(62 flights)
  • Fri73%(63 flights)
  • Sat73%(64 flights)
  • Sun61%(66 flights)
On-time by departure window
  • 6–9 AM90%(10 flights)
  • 12–3 PM91%(11 flights)
  • 3–6 PM80%(56 flights)
  • 6–9 PM67%(361 flights)
On-time trend by month
75%
May

Jun 63% → May 75% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202563%30
July 202547%30
August 202552%31
September 202569%29
October 202571%35
November 202581%58
December 202556%32
January 202668%31
February 202682%28
March 202671%31
April 202690%31
May 202675%72
Departures on time
71%
Diverted
0.5%
Flights flown
438
Months covered
12

Same route, other flights

Keep nerding

Based on 442 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.