Flight number record
F9 1230
Frontier Airlines · San Francisco to Denver
- Route
- SFO → DEN
- Departs
- 06:00
- Flights
- 346
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s F9 1230, check with Frontier Airlines.
F9 1230 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 346 flights, with a median arrival 10 minutes early.
Set against the rest of the country, F9 1230's record is 10 points better than the US average of 77.6%. That gap is worth roughly 95 fewer late arrivals for every thousand flights.
Key figures
On time
87.1%
Arrivals under 15 minutes late, of 342 completed flights
Avg delay
67 min
Across delayed arrivals only, not all flights
Cancelled
1.16%
National rate is 1.81%
1 hour+ late
3.5%
National rate is 8.1%
These figures cover 346 flights between July 2025 and June 2026. The median arrival is 10 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 1230 flies
F9 1230 flies SFO to DEN without a single fixed slot. Its most common scheduled departure was 06:00, used on 113 of 346 flights, with 06:37 (49 flights) and 06:34 (35 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 06:00113 flights32.7%
- Departs 06:3749 flights14.2%
- Departs 06:3435 flights10.1%
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 06:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and F9 1230 runs 2 points worse at 87.1%. 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 1230 next to SFO to DEN
Every carrier on SFO to DEN combined arrived on time 75.5% of the time across 5,410 flights, so F9 1230 is 12 points ahead of it. Frontier flew 604 flights on the same city pair under all its flight numbers, including this one, and those ran 73.2% on time. Across its whole network Frontier Airlines managed 73.2%, which this flight beats by 14 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 1230thin sample | 346 | 87.1% | 67 min | 1.16% | A |
| All Frontier Airlines on SFO–DEN | 604 | 73.2% | 61 min | 0.99% | C+ |
| All carriers on SFO–DEN | 5,410 | 75.5% | 59 min | 0.46% | B+ |
| Frontier Airlines, whole network | 205,332 | 73.2% | 84 min | 1.85% | C |
Across the year
F9 1230 quarter by quarter
F9 1230 did not run the same all year. Its best quarter was Apr–Jun 2026 at 92.1% on time and its weakest Jul–Sep 2025 at 79.3%, a swing of 13 points on roughly 87 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 202588 flights79.3%
- Oct–Dec 202591 flights87.9%
- Jan–Mar 202676 flights89.3%
- Apr–Jun 202691 flights92.1%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, F9 1230 ranged from 82.6% on Wednesday to 92.3% on Sunday. With about 49 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.
Delay causes
Why F9 1230 runs late
One category carries most of the weight here. Carrier accounts for 59% of the 2,949 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 59%Carrier
- 23%National Airspace System
- 17%Late-arriving aircraft
The largest share of delay minutes, 59%, 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 1,744 of the 2,949 delay minutes reported here. The split is drawn from 2,949 delay minutes reported on F9 1230.
Cancellations sit at 1.16% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.5% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
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. 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 346 flights under F9 1230 in the data flew SFO 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. 346 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 1230
For a booking, F9 1230 has one of the better records a US domestic flight can show: 87.1% on time and 1.16% cancelled. That is a base rate, not a promise about any single day.
Related
Where to go next
- SFO to DEN, every carrier and departure
- DEN to SFO, the return direction
- United Airlines 2348 on the same route86.3%
- San Francisco International (SFO) 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
- Worst months to fly in the US, ranked by the data
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.