Flight Reliability
F9 1230 · Frontier Airlines
San Francisco → Denver (SFO–DEN)
91
Nerd Approved
WanderNerd Reliability Score
- 87%
- Arrive within 15 minutes
- 0 min
- Average arrival delay
- 1.2%
- Cancelled
- 7 min early
- Median arrival delay
Based on 343 historical flights. Data through May 2026.
What the data says
Wednesday is the weak spot.
F9 1230 arrived on time 93% of the time on Sundays. On Wednesdays: 84%.
Better than the SFO–DEN route average.
F9 1230 arrived on time 87% of the time, versus 77% across the SFO–DEN route.
Better than the Frontier Airlines network average.
F9 1230 arrived on time 87% of the time, versus 73% across the Frontier Airlines network.
The breakdown
- Mon88%(51 flights)
- Tue84%(45 flights)
- Wed84%(44 flights)
- Thu89%(52 flights)
- Fri86%(51 flights)
- Sat86%(43 flights)
- Sun93%(53 flights)
94%
May
Jun 82% → May 94% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 82% | 27 |
| July 2025 | 83% | 30 |
| August 2025 | 74% | 31 |
| September 2025 | 85% | 26 |
| October 2025 | 87% | 30 |
| November 2025 | 93% | 30 |
| December 2025 | 87% | 31 |
| January 2026 | 96% | 25 |
| February 2026 | 86% | 22 |
| March 2026 | 89% | 28 |
| April 2026 | 93% | 28 |
| May 2026 | 94% | 31 |
- Departures on time
- 91%
- Diverted
- 0%
- Flights flown
- 339
- Months covered
- 12
Same route, other flights
Keep nerding
Based on 343 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.