About 1 in 2 F9 3999 flights from Dallas arrived 15+ minutes late, diverted or cancelled over the past year (50%); 3.8% were cancelled. The typical flight landed 12 minutes late.
F9 3999: DFW → SFO
Scheduled to leave Dallas at 8:59 p.m. local time. Over the past year it arrived on time 50% of the time (213 flights), better than other F9 flights on the route at that hour (39%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 42 | 43% |
| Tuesday | 20 | 60% |
| Wednesday | 17 | — |
| Thursday | 34 | 47% |
| Friday | 40 | 57% |
| Saturday | 22 | 77% |
| Sunday | 38 | 32% |
Why it was late
All flights DFW → SFO · Connecting off F9 3999? Check the risk
Questions
How often is F9 3999 from DFW to SFO late?
Frontier Airlines 3999 from Dallas/Fort Worth, TX to San Francisco, CA arrived 15 or more minutes late, was diverted or was cancelled on 50% of 213 scheduled flights between September 2025 and August 2026. 3.8% 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.