Flight number record
F9 3439
Frontier Airlines · Denver to San Francisco
- Route
- DEN → SFO
- Departs
- 22:29
- Flights
- 284
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s F9 3439, check with Frontier Airlines.
F9 3439 sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 284 flights, with a median arrival 1 minute early.
The national on-time rate over the same period is 77.3%, so F9 3439 runs 7 points behind the country as a whole. Across a thousand flights that is about 70 extra late arrivals.
Key figures
On time
70.3%
Arrivals under 15 minutes late, of 276 completed flights
Avg delay
58 min
Across delayed arrivals only, not all flights
Cancelled
2.46%
National rate is 1.89%
1 hour+ late
8.3%
National rate is 8.3%
These figures cover 284 flights between September 2025 and August 2026. Beyond the headline rate, 8.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When F9 3439 flies
F9 3439 is scheduled to leave Denver (DEN) at 22:29 local time and reach San Francisco (SFO) at 00:28. That slot held for 271 of the 284 scheduled departures in the data, so the figures below describe one steady operation rather than a number that moved around the clock.
- Departs 22:29271 flights95.4%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 22:29 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and F9 3439 runs level with that at 70.3%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
F9 3439 next to DEN to SFO
Every carrier on DEN to SFO combined arrived on time 63.2% of the time across 5,488 flights, so F9 3439 is 7 points ahead of it. Frontier flew 667 flights on the same city pair under all its flight numbers, including this one, and those ran 64.0% on time. Across its whole network Frontier Airlines managed 72.7%, which this flight trails by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 3439thin sample | 284 | 70.3% | 58 min | 2.46% | C |
| All Frontier Airlines on DEN–SFO | 667 | 64.0% | 60 min | 1.05% | D |
| All carriers on DEN–SFO | 5,488 | 63.2% | 62 min | 0.40% | D+ |
| Frontier Airlines, whole network | 213,022 | 72.7% | 84 min | 2.05% | C |
Across the year
F9 3439 quarter by quarter
F9 3439 did not run the same all year. Its best quarter was Jan–Mar 2026 at 84.1% on time and its weakest Jul–Sep 2026 at 55.9%, a swing of 28 points on roughly 71 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202517 flights—
- Oct–Dec 202566 flights76.9%
- Jan–Mar 202665 flights84.1%
- Apr–Jun 202674 flights66.7%
- Jul–Sep 202662 flights55.9%
Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, F9 3439 did best on Saturday at 80.6% on time and worst on Sunday at 57.4%. Each day rests on about 41 flights, so a gap of 23 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late F9 3439 runs when it is late
F9 3439 often beats the schedule: 81 of 276 completed flights, 29%, arrived 15 minutes or more early. The 82 late arrivals split 25 under half an hour, 34 between 30 and 60 minutes, and 23 an hour or more.
- 15+ min early81 flights29.3%
- Within 15 min113 flights40.9%
- 15–29 min late25 flights9.1%
- 30–59 min late34 flights12.3%
- 1–2 hours late16 flights5.8%
- 2+ hours late7 flights2.5%
Scale runs 0% to 100%.
Share of 276 completed flights by arrival against schedule.
A late pushback is often recovered here: of 95 departures that left 15 minutes late or more, 34 still arrived on time. In the other direction, 21 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SFO.
The worst days
Worst days for F9 3439
The latest arrival of the period was on 24 August 2026, 7 hours 3 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across August, March, July and October, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 24 August 2026 | 7 hours 3 minutes | Carrier |
| 13 August 2026 | 4 hours 3 minutes | Late-arriving aircraft |
| 22 March 2026 | 2 hours 50 minutes | Extreme weather |
| 8 July 2026 | 2 hours 44 minutes | Carrier |
| 10 October 2025 | 2 hours 33 minutes | Late-arriving aircraft |
Delay causes
Why F9 3439 runs late
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 4,757 reported delay minutes.
- 36%Late-arriving aircraft
- 35%Carrier
- 23%National Airspace System
- 5%Extreme weather
36% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,757 reported delay minutes here, that single category outweighs weather by 7 to one. The split is drawn from 4,757 delay minutes reported on F9 3439.
Cancellations sit at 2.46% against a national 1.89%, which is ordinary. Diversions add another 0.35%.
Connections and routes
What a delay on this flight costs
8.3% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
The 967 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
Every one of the 284 flights under F9 3439 in the data flew DEN to SFO. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 284 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking F9 3439
For a booking, read F9 3439 as 70.3% on time with 2.46% cancelled over 284 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- DEN to SFO, every carrier and departure
- SFO to DEN, the return direction
- United Airlines 1812 on the same route73.4%
- United Airlines 2633 on the same route68.7%
- United Airlines 2391 on the same route71.7%
- United Airlines 2367 on the same route95.3%
- United Airlines 1007 on the same route66.2%
- United Airlines 1561 on the same route66.8%
- Denver International (DEN) delay statistics
- San Francisco International (SFO) delay statistics
- Frontier Airlines on-time record
- Every Frontier Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
A flight number here means Frontier Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.