Flight number record
F9 3406
Frontier Airlines · Seattle to Denver
- Route
- SEA → DEN
- Departs
- 12:35
- Flights
- 284
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s F9 3406, check with Frontier Airlines.
F9 3406 sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.3%. The late ones land a little over an hour behind schedule. That rests on 284 flights, with a median arrival 4 minutes early.
Key figures
On time
75.0%
Arrivals under 15 minutes late, of 280 completed flights
Avg delay
73 min
Across delayed arrivals only, not all flights
Cancelled
1.06%
National rate is 1.89%
1 hour+ late
8.2%
National rate is 8.3%
These figures cover 284 flights between September 2025 and August 2026. Beyond the headline rate, 8.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When F9 3406 flies
F9 3406 flies SEA to DEN without a single fixed slot. Its most common scheduled departure was 12:35, used on 31 of 284 flights.
- Departs 12:3531 flights10.9%
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 12:35 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and F9 3406 runs 3 points worse at 75.0%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
F9 3406 next to SEA to DEN
Every carrier on SEA to DEN combined arrived on time 78.3% of the time across 6,333 flights, so F9 3406 is 3 points behind it. Frontier flew 439 flights on the same city pair under all its flight numbers, including this one, and those ran 76.0% on time. Across its whole network Frontier Airlines managed 72.7%, which this flight beats by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 3406thin sample | 284 | 75.0% | 73 min | 1.06% | B |
| All Frontier Airlines on SEA–DEN | 439 | 76.0% | 74 min | 0.91% | B+ |
| All carriers on SEA–DEN | 6,333 | 78.3% | 58 min | 0.68% | B+ |
| Frontier Airlines, whole network | 213,022 | 72.7% | 84 min | 2.05% | C |
Across the year
F9 3406 quarter by quarter
F9 3406 did not run the same all year. Its best quarter was Jan–Mar 2026 at 81.0% on time and its weakest Jul–Sep 2026 at 63.9%, a swing of 17 points on roughly 57 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 202530 flights70.0%
- Oct–Dec 202580 flights77.5%
- Jan–Mar 202658 flights81.0%
- Apr–Jun 202654 flights80.4%
- Jul–Sep 202662 flights63.9%
Scale runs 55% to 85%.
By weekday, F9 3406 ranged from 72.0% on Monday to 83.7% on Sunday. With about 41 flights behind each day, a spread of 12 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late F9 3406 runs when it is late
F9 3406 often beats the schedule: 80 of 280 completed flights, 29%, arrived 15 minutes or more early. The 70 late arrivals split 26 under half an hour, 21 between 30 and 60 minutes, and 23 an hour or more.
- 15+ min early80 flights28.6%
- Within 15 min130 flights46.4%
- 15–29 min late26 flights9.3%
- 30–59 min late21 flights7.5%
- 1–2 hours late14 flights5.0%
- 2+ hours late9 flights3.2%
Scale runs 0% to 100%.
Share of 280 completed flights by arrival against schedule.
18 of 70 late departures made up the time and arrived on time, 26% of them. In the other direction, 18 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 DEN.
The worst days
Worst days for F9 3406
The latest arrival of the period was on 24 August 2026, 18 hours 52 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. Three of the five worst days fell in August 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 24 August 2026 | 18 hours 52 minutes | Late-arriving aircraft |
| 14 August 2026 | 5 hours 58 minutes | Late-arriving aircraft |
| 19 December 2025 | 3 hours 9 minutes | Late-arriving aircraft |
| 12 September 2025 | 2 hours 33 minutes | Carrier |
| 13 August 2026 | 2 hours 22 minutes | National Airspace System |
Delay causes
Why F9 3406 runs late
Late-arriving aircraft accounts for 48% of the 5,105 delay minutes carriers reported here, and the remaining four split what is left.
- 48%Late-arriving aircraft
- 34%National Airspace System
- 17%Carrier
- 1%Extreme weather
48% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,105 reported delay minutes here, that single category outweighs weather by 47 to one. The split is drawn from 5,105 delay minutes reported on F9 3406.
Cancellations sit at 1.06% against a national 1.89%, which is ordinary. Diversions add another 0.35%.
Connections and routes
What a delay on this flight costs
8.2% 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 a little over an hour, which a normal layover absorbs.
The 1,024 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 3406 in the data flew SEA to DEN. 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 3406
For a booking, read F9 3406 as 75.0% on time with 1.06% cancelled over 284 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SEA to DEN, every carrier and departure
- DEN to SEA, the return direction
- United Airlines 757 on the same route85.4%
- United Airlines 1505 on the same route91.1%
- Alaska Airlines 602 on the same route74.7%
- Alaska Airlines 682 on the same route86.1%
- Delta Air Lines 2851 on the same route76.1%
- Seattle-Tacoma International (SEA) delay statistics
- Denver International (DEN) 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.