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Flight Reliability

F9 4236 · Frontier Airlines

Salt Lake City → Denver (SLC–DEN)

83
Pretty Reliable
WanderNerd Reliability Score
80%
Arrive within 15 minutes
13 min
Average arrival delay
0.9%
Cancelled
8 min early
Median arrival delay

Based on 106 historical flights. Data through May 2026.

What the data says

The 12–3 PM departure wins.

F9 4236 departing between 12–3 PM arrived on time 88% of the time, versus 75% between 3–6 PM.

Friday is doing you no favors.

F9 4236 arrived on time 100% of the time on Saturdays and just 68% on Fridays. That gap is worth planning around.

A bit ahead of the Frontier Airlines network.

F9 4236 arrived on time 80% of the time, versus 73% across the Frontier Airlines network.

The breakdown

On-time by weekday
  • Mon90%(19 flights)
  • Tue71%(14 flights)
  • Wed75%(12 flights)
  • Thu71%(14 flights)
  • Fri68%(19 flights)
  • Sat100%(13 flights)
  • Sun86%(14 flights)
On-time by departure window
  • 12–3 PM88%(16 flights)
  • 3–6 PM75%(51 flights)
  • 6–9 PM83%(35 flights)
  • 9 PM–12 AM—(3 flights)
On-time trend by month
70%
May

Oct 83% → May 70% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
October 202583%12
December 202571%17
January 202688%16
February 202683%18
May 202670%27
Departures on time
80%
Diverted
0%
Flights flown
105
Months covered
8

Same route, other flights

Keep nerding

Based on 106 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.