About 1 in 3 F9 3439 flights from Denver arrived 15+ minutes late, diverted or cancelled over the past year (32%); 2.5% were cancelled. The typical flight landed 1 minutes early.
F9 3439: DEN → SFO
Scheduled to leave Denver at 10:29 p.m. local time. Over the past year it arrived on time 68% of the time (284 flights), in line with other F9 flights on the route at that hour (70%). Last seen in the data Aug 31, 2026.
Usually Frontier Airlines's last flight of the day from Denver to San Francisco (91% of days). Frontier Airlines's last DEN–SFO flight was cancelled 2.6% of the time, against 0.0% for its earlier ones. If it's cancelled, the next Frontier Airlines flight is usually around 9:49 a.m. the next morning.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 53 | 68% |
| Tuesday | 25 | 76% |
| Wednesday | 22 | 45% |
| Thursday | 51 | 76% |
| Friday | 52 | 73% |
| Saturday | 31 | 81% |
| Sunday | 50 | 54% |
Why it was late
All flights DEN → SFO · Connecting off F9 3439? Check the risk
Questions
How often is F9 3439 from DEN to SFO late?
Frontier Airlines 3439 from Denver, CO to San Francisco, CA arrived 15 or more minutes late, was diverted or was cancelled on 32% of 284 scheduled flights between September 2025 and August 2026. 2.5% were cancelled.
Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check Frontier Airlines for today's flight. Method.