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Flight Reliability

F9 1229 · Frontier Airlines

Denver → San Francisco (DEN–SFO)

89
Pretty Reliable
WanderNerd Reliability Score
81%
Arrive within 15 minutes
3 min
Average arrival delay
0%
Cancelled
9 min early
Median arrival delay

Based on 146 historical flights. Data through May 2026.

What the data says

The late departure is the smart one here.

F9 1229 departing between 9 PM–12 AM arrived on time 100% of the time, versus 50% between 9 AM–12 PM.

Sunday scaries are real for this one.

F9 1229 arrived on time 89% of the time on Fridays and just 70% on Sundays. That gap is worth planning around.

Better than the DEN–SFO route average.

F9 1229 arrived on time 81% of the time, versus 69% across the DEN–SFO route.

Better than the Frontier Airlines network average.

F9 1229 arrived on time 81% of the time, versus 73% across the Frontier Airlines network.

The breakdown

On-time by weekday
  • Mon85%(27 flights)
  • Tue80%(10 flights)
  • Wed—(8 flights)
  • Thu79%(29 flights)
  • Fri89%(27 flights)
  • Sat80%(15 flights)
  • Sun70%(30 flights)
On-time by departure window
  • 6–9 AM92%(71 flights)
  • 9 AM–12 PM50%(22 flights)
  • 12–3 PM74%(19 flights)
  • 3–6 PM65%(17 flights)
  • 9 PM–12 AM100%(17 flights)
On-time trend by month
58%
May

Jun 64% → May 58% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202564%14
September 202588%17
October 202572%18
November 202586%21
December 202582%17
February 2026100%10
April 202690%10
May 202658%19
Departures on time
82%
Diverted
0%
Flights flown
146
Months covered
11

Same route, other flights

Keep nerding

Based on 146 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.