Flight Reliability
F9 4139 · Frontier Airlines
San Juan → Cleveland (SJU–CLE)
66
Usually Fine
WanderNerd Reliability Score
- 79%
- Arrive within 15 minutes
- 1 min
- Average arrival delay
- 5.3%
- Cancelled
- 11 min early
- Median arrival delay
Based on 94 historical flights. Data through May 2026.
What the data says
The 3–6 AM departure wins.
F9 4139 departing between 3–6 AM arrived on time 100% of the time, versus 74% between 6–9 AM.
Mondays have been rough.
F9 4139 arrived on time 91% of the time on Tuesdays and just 67% on Mondays. That gap is worth planning around.
A bit ahead of the Frontier Airlines network.
F9 4139 arrived on time 79% of the time, versus 73% across the Frontier Airlines network.
The breakdown
- Mon67%(15 flights)
- Tue91%(11 flights)
- Wed73%(11 flights)
- Thu86%(14 flights)
- Fri83%(12 flights)
- Sat75%(12 flights)
- Sun79%(14 flights)
- 3–6 AM100%(14 flights)
- 6–9 AM74%(38 flights)
- 12–3 PM74%(35 flights)
- 3–6 PM—(2 flights)
93%
Dec
Jun 88% → Dec 93% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 88% | 24 |
| July 2025 | 77% | 30 |
| August 2025 | 77% | 17 |
| December 2025 | 93% | 14 |
- Departures on time
- 82%
- Diverted
- 0%
- Flights flown
- 89
- Months covered
- 5
Keep nerding
Based on 94 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.