Flight Reliability
F9 3731 · Frontier Airlines
Washington → Miami (IAD–MIA)
68
Usually Fine
WanderNerd Reliability Score
- 71%
- Arrive within 15 minutes
- 9 min
- Average arrival delay
- 2.7%
- Cancelled
- 4 min early
- Median arrival delay
Based on 112 historical flights. Data through May 2026.
What the data says
The late departure is the smart one here.
F9 3731 departing between 6–9 PM arrived on time 80% of the time, versus 50% between 9 PM–12 AM.
Friday is doing you no favors.
F9 3731 arrived on time 77% of the time on Thursdays. On Fridays: 68%.
Lagging the IAD–MIA route.
F9 3731 arrived on time 71% of the time, versus 80% across the IAD–MIA route.
Trending in the right direction.
F9 3731 arrived on time 81% of the time over the last three months in the data, compared with 69% in the three months before that.
The breakdown
- Mon69%(32 flights)
- Tue—(0 flights)
- Wed—(1 flights)
- Thu77%(13 flights)
- Fri68%(34 flights)
- Sat—(4 flights)
- Sun68%(25 flights)
- 9 AM–12 PM—(5 flights)
- 12–3 PM73%(11 flights)
- 3–6 PM78%(50 flights)
- 6–9 PM80%(15 flights)
- 9 PM–12 AM50%(28 flights)
92%
Dec
Jul 60% → Dec 92% on time
| Month | On-time percentage | Flights |
|---|---|---|
| July 2025 | 60% | 10 |
| August 2025 | 65% | 17 |
| September 2025 | 82% | 17 |
| October 2025 | 78% | 18 |
| November 2025 | 71% | 14 |
| December 2025 | 92% | 13 |
- Departures on time
- 74%
- Diverted
- 0%
- Flights flown
- 109
- Months covered
- 11
Same route, other flights
Keep nerding
Based on 112 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.