Flight Reliability
F9 1248 · Frontier Airlines
Denver → Grand Rapids (DEN–GRR)
94
Nerd Approved
WanderNerd Reliability Score
- 86%
- Arrive within 15 minutes
- 0 min
- Average arrival delay
- 0%
- Cancelled
- 9 min early
- Median arrival delay
Based on 147 historical flights. Data through May 2026.
What the data says
The 12–3 PM departure wins.
F9 1248 departing between 12–3 PM arrived on time 93% of the time, versus 80% between 9 AM–12 PM.
Sunday scaries are real for this one.
F9 1248 arrived on time 95% of the time on Saturdays and just 74% on Sundays. That gap is worth planning around.
Better than the DEN–GRR route average.
F9 1248 arrived on time 86% of the time, versus 75% across the DEN–GRR route.
Better than the Frontier Airlines network average.
F9 1248 arrived on time 86% of the time, versus 73% across the Frontier Airlines network.
The breakdown
- Mon89%(35 flights)
- Tue—(1 flights)
- Wed86%(14 flights)
- Thu79%(14 flights)
- Fri94%(35 flights)
- Sat95%(21 flights)
- Sun74%(27 flights)
- 9 AM–12 PM80%(20 flights)
- 12–3 PM93%(28 flights)
- 3–6 PM86%(99 flights)
92%
May
Jun 75% → May 92% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 75% | 20 |
| July 2025 | 86% | 21 |
| August 2025 | 91% | 23 |
| September 2025 | 91% | 21 |
| October 2025 | 78% | 18 |
| November 2025 | 82% | 11 |
| April 2026 | 90% | 10 |
| May 2026 | 92% | 13 |
- Departures on time
- 85%
- Diverted
- 0%
- Flights flown
- 147
- Months covered
- 10
Same route, other flights
Keep nerding
Based on 147 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.