ON TIMEBOARD

F9 4345 on time

Frontier Airlines 4345: Denver to Los Angeles at 10:39 p.m. (past 12 months)

On time
74%
306 flights · likely 69–79%
Cancelled
1.0%
of scheduled flights
Typical arrival
−9 min
median vs schedule
When late
+61 min
average delay
Similar flights
75%
F9, same route & hour

About 1 in 4 F9 4345 flights from Denver arrived 15+ minutes late, diverted or cancelled over the past year (26%); 1.0% were cancelled. The typical flight landed 9 minutes early.

F9 4345: DEN → LAX

Scheduled to leave Denver at 10:39 p.m. local time. Over the past year it arrived on time 74% of the time (306 flights), in line with other F9 flights on the route at that hour (75%). Last seen in the data Aug 31, 2026.

Usually Frontier Airlines's last flight of the day from Denver to Los Angeles (100% of days). Frontier Airlines's last DEN–LAX flight was cancelled 0.9% of the time, against 0.7% for its earlier ones. If it's cancelled, the next Frontier Airlines flight is usually around 7:00 a.m. the next morning.

Month by month

40%70%100%Sep 2025: 73% on time (26 flights)73SepOct 2025: 87% on time (30 flights)87OctNov 2025: 83% on time (30 flights)83NovDec 2025: 55% on time (20 flights)55DecJan 2026: 59% on time (17 flights)59JanFeb 2026: 84% on time (19 flights)84FebMar 2026: 79% on time (29 flights)79MarApr 2026: 73% on time (22 flights)73AprMay 2026: 91% on time (22 flights)91MayJun 2026: 63% on time (30 flights)63JunJul 2026: 67% on time (30 flights)67JulAug 2026: 71% on time (31 flights)71Aug

By day of week

DayFlightsOn time
Monday5374%
Tuesday3485%
Wednesday3476%
Thursday4978%
Friday5263%
Saturday3367%
Sunday5178%

Why it was late

Airline (crew, maintenance, ops) 51%Late inbound plane 40%Air traffic & airport (NAS) 6%Severe weather 2%

All flights DEN → LAX · Connecting off F9 4345? Check the risk

Questions

How often is F9 4345 from DEN to LAX late?

Frontier Airlines 4345 from Denver, CO to Los Angeles, CA arrived 15 or more minutes late, was diverted or was cancelled on 26% of 306 scheduled flights between September 2025 and August 2026. 1.0% were cancelled.

Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check Frontier Airlines for today's flight. Method.