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Flight Reliability

F9 4578 · Frontier Airlines

San Diego → Phoenix (SAN–PHX)

65
Usually Fine
WanderNerd Reliability Score
65%
Arrive within 15 minutes
16 min
Average arrival delay
1.1%
Cancelled
4 min
Median arrival delay

Based on 177 historical flights. Data through May 2026.

What the data says

The 3–6 PM departure wins.

F9 4578 departing between 3–6 PM arrived on time 78% of the time, versus 60% between 12–3 PM.

Thursdays have been rough.

F9 4578 arrived on time 91% of the time on Saturdays and just 44% on Thursdays. That gap is worth planning around.

Lagging the SAN–PHX route.

F9 4578 arrived on time 65% of the time, versus 77% across the SAN–PHX route.

Lagging the Frontier Airlines network.

F9 4578 arrived on time 65% of the time, versus 73% across the Frontier Airlines network.

The breakdown

On-time by weekday
  • Mon67%(33 flights)
  • Tue77%(13 flights)
  • Wed64%(11 flights)
  • Thu44%(27 flights)
  • Fri59%(32 flights)
  • Sat91%(22 flights)
  • Sun62%(37 flights)
On-time by departure window
  • 6–9 AM—(2 flights)
  • 9 AM–12 PM69%(16 flights)
  • 12–3 PM60%(124 flights)
  • 3–6 PM78%(23 flights)
  • 6–9 PM—(3 flights)
  • 9 PM–12 AM—(7 flights)
On-time trend by month
56%
May

Jun 53% → May 56% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202553%19
July 202557%21
August 202547%19
September 202582%17
October 202571%14
March 202673%22
April 202671%24
May 202656%18
Departures on time
62%
Diverted
0%
Flights flown
175
Months covered
12

Same route, other flights

Keep nerding

Based on 177 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.