Flight number record
F9 4989
Frontier Airlines · Denver to San Diego
- Route
- DEN → SAN
- Departs
- 22:29
- Flights
- 256
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s F9 4989, check with Frontier Airlines.
F9 4989 sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 256 flights, with a median arrival 4 minutes early.
Key figures
On time
73.6%
Arrivals under 15 minutes late, of 250 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
1.95%
National rate is 1.89%
1 hour+ late
8.4%
National rate is 8.3%
These figures cover 256 flights between September 2025 and August 2026. Beyond the headline rate, 8.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When F9 4989 flies
F9 4989 is scheduled to leave Denver (DEN) at 22:29 local time and reach San Diego (SAN) at 23:51. That slot held for 222 of the 256 scheduled departures in the data, so the figures below describe one steady operation rather than a number that moved around the clock.
- Departs 22:29222 flights86.7%
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 4989 runs 4 points better at 73.6%. 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 4989 next to DEN to SAN
Every carrier on DEN to SAN combined arrived on time 73.8% of the time across 6,152 flights, so F9 4989 is about level with it. Frontier flew 701 flights on the same city pair under all its flight numbers, including this one, and those ran 80.1% on time. Across its whole network Frontier Airlines managed 72.7%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 4989thin sample | 256 | 73.6% | 57 min | 1.95% | C |
| All Frontier Airlines on DEN–SAN | 701 | 80.1% | 66 min | 1.43% | B |
| All carriers on DEN–SAN | 6,152 | 73.8% | 56 min | 0.83% | C+ |
| Frontier Airlines, whole network | 213,022 | 72.7% | 84 min | 2.05% | C |
Across the year
F9 4989 quarter by quarter
F9 4989 did not run the same all year. Its best quarter was Jan–Mar 2026 at 82.8% on time and its weakest Jul–Sep 2026 at 62.7%, a swing of 20 points on roughly 64 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 20259 flights—
- Oct–Dec 202545 flights70.5%
- Jan–Mar 202666 flights82.8%
- Apr–Jun 202674 flights77.0%
- Jul–Sep 202662 flights62.7%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, F9 4989 did best on Saturday at 83.9% on time and worst on Sunday at 68.9%. Each day rests on about 37 flights, so a gap of 15 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late F9 4989 runs when it is late
F9 4989 often beats the schedule: 76 of 250 completed flights, 30%, arrived 15 minutes or more early. The 66 late arrivals split 18 under half an hour, 27 between 30 and 60 minutes, and 21 an hour or more.
- 15+ min early76 flights30.4%
- Within 15 min108 flights43.2%
- 15–29 min late18 flights7.2%
- 30–59 min late27 flights10.8%
- 1–2 hours late15 flights6.0%
- 2+ hours late6 flights2.4%
Scale runs 0% to 100%.
Share of 250 completed flights by arrival against schedule.
23 of 83 late departures made up the time and arrived on time, 28% of them. 6 flights left on time and still arrived late.
The worst days
Worst days for F9 4989
The latest arrival of the period was on 10 August 2026, 2 hours 46 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, December, July and March, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 10 August 2026 | 2 hours 46 minutes | Carrier |
| 19 December 2025 | 2 hours 44 minutes | National Airspace System |
| 14 August 2026 | 2 hours 40 minutes | Late-arriving aircraft |
| 28 July 2026 | 2 hours 15 minutes | Carrier |
| 6 March 2026 | 2 hours 6 minutes | Late-arriving aircraft |
Delay causes
Why F9 4989 runs late
Late-arriving aircraft accounts for 48% of the 3,773 delay minutes carriers reported here, and the remaining four split what is left.
- 48%Late-arriving aircraft
- 33%Carrier
- 18%National Airspace System
- 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 3,773 reported delay minutes here, that single category outweighs weather by 35 to one. The split is drawn from 3,773 delay minutes reported on F9 4989.
Cancellations sit at 1.95% against a national 1.89%, which is ordinary. Diversions add another 0.39%.
Connections and routes
What a delay on this flight costs
8.4% 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 853 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 256 flights under F9 4989 in the data flew DEN to SAN. 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. 256 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 4989
For a booking, read F9 4989 as 73.6% on time with 1.95% cancelled over 256 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- DEN to SAN, every carrier and departure
- SAN to DEN, the return direction
- United Airlines 1940 on the same route78.4%
- United Airlines 540 on the same route63.5%
- United Airlines 1302 on the same route83.6%
- United Airlines 2309 on the same route90.9%
- United Airlines 1281 on the same route83.3%
- Denver International (DEN) delay statistics
- San Diego International (SAN) 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.