Flight number record
F9 3406
Frontier Airlines · Seattle to Denver
- Route
- SEA → DEN
- Departs
- 06:25
- Flights
- 284
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 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 77.6%. The late ones land about an hour behind schedule. That rests on 284 flights, with a median arrival 3 minutes early.
Key figures
On time
75.6%
Arrivals under 15 minutes late, of 279 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
1.76%
National rate is 1.81%
1 hour+ late
7.9%
National rate is 8.1%
These figures cover 284 flights between July 2025 and June 2026. The median arrival is 3 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Schedule
When F9 3406 flies
F9 3406 flies SEA to DEN without a single fixed slot. Its most common scheduled departure was 06:25, used on 51 of 284 flights. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 06:2551 flights18.0%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 06:25 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and F9 3406 runs 14 points worse at 75.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Against the route
F9 3406 next to SEA to DEN
Every carrier on SEA to DEN combined arrived on time 77.8% of the time across 6,317 flights, so F9 3406 is 2 points behind it. Across its whole network Frontier Airlines managed 73.2%, which this flight beats by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 3406thin sample | 284 | 75.6% | 59 min | 1.76% | B |
| All Frontier Airlines on SEA–DEN | 419 | 74.9% | 75 min | 1.91% | C |
| All carriers on SEA–DEN | 6,317 | 77.8% | 58 min | 0.85% | B+ |
| Frontier Airlines, whole network | 205,332 | 73.2% | 84 min | 1.85% | 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 2025 at 67.8%, a swing of 13 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 202592 flights67.8%
- Oct–Dec 202580 flights77.5%
- Jan–Mar 202658 flights81.0%
- Apr–Jun 202654 flights80.4%
Scale runs 60% to 85%. Rows with fewer than 30 flights show a dash.
By weekday, F9 3406 did best on Sunday at 85.4% on time and worst on Monday at 64.6%. Each day rests on about 41 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Delay causes
Why F9 3406 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 4,014 reported delay minutes.
- 35%Carrier
- 32%National Airspace System
- 27%Late-arriving aircraft
- 7%Extreme weather
The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 1,393 of the 4,014 delay minutes reported here. The split is drawn from 4,014 delay minutes reported on F9 3406.
Cancellations sit at 1.76% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
7.9% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
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 75.6% on time with 1.76% 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 route85.5%
- Alaska Airlines 682 on the same route83.8%
- United Airlines 1505 on the same route91.0%
- Alaska Airlines 602 on the same route72.7%
- 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
- The best time of day to fly, according to 7.04 million flight records
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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.