About 1 in 2 F9 3440 flights from San Francisco arrived 15+ minutes late, diverted or cancelled over the past year (44%); 0.0% were cancelled. The typical flight landed 11 minutes late.
F9 3440: SFO → DEN
Scheduled to leave San Francisco at 9:39 p.m. local time. Over the past year it arrived on time 56% of the time (133 flights), better than other F9 flights on the route at that hour (38%). Last seen in the data Aug 31, 2026.
Usually Frontier Airlines's last flight of the day from San Francisco to Denver (81% of days). Frontier Airlines's last SFO–DEN flight was cancelled 0.8% of the time, against 1.7% for its earlier ones. If it's cancelled, the next Frontier Airlines flight is usually around 6:00 a.m. the next morning.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 26 | 46% |
| Tuesday | 6 | — |
| Wednesday | 8 | — |
| Thursday | 16 | — |
| Friday | 31 | 61% |
| Saturday | 20 | 55% |
| Sunday | 26 | 54% |
Why it was late
All flights SFO → DEN · Connecting off F9 3440? Check the risk
Questions
How often is F9 3440 from SFO to DEN late?
Frontier Airlines 3440 from San Francisco, CA to Denver, CO arrived 15 or more minutes late, was diverted or was cancelled on 44% of 133 scheduled flights between September 2025 and August 2026. 0.0% 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.