ON TIMEBOARD

DL 4099 on time

Delta Air Lines 4099: Los Angeles to Reno at 8:20 a.m.; Reno to Los Angeles at 10:34 a.m. (past 12 months). Figures below the title are for LAX → RNO, its busiest leg

On time
95%
365 flights · likely 92–97%
Cancelled
0.5%
of scheduled flights
Typical arrival
−16 min
median vs schedule
When late
+64 min
average delay
Similar flights
97%
DL, same route & hour

About 1 in 19 DL 4099 flights from Los Angeles arrived 15+ minutes late, diverted or cancelled over the past year (5%); 0.5% were cancelled. The typical flight landed 16 minutes early.

DL 4099: LAX → RNO

Scheduled to leave Los Angeles at 8:20 a.m. local time, operated by SkyWest as OO 4099. Over the past year it arrived on time 95% of the time (365 flights), in line with other DL flights on the route at that hour (97%). Last seen in the data Aug 31, 2026.

Month by month

40%70%100%Sep 2025: 100% on time (30 flights)100SepOct 2025: 90% on time (31 flights)90OctNov 2025: 90% on time (30 flights)90NovDec 2025: 87% on time (31 flights)87DecJan 2026: 90% on time (31 flights)90JanFeb 2026: 93% on time (28 flights)93FebMar 2026: 97% on time (31 flights)97MarApr 2026: 100% on time (30 flights)100AprMay 2026: 97% on time (31 flights)97MayJun 2026: 100% on time (30 flights)100JunJul 2026: 97% on time (31 flights)97JulAug 2026: 97% on time (31 flights)97Aug

By day of week

DayFlightsOn time
Monday5398%
Tuesday5296%
Wednesday5292%
Thursday5294%
Friday5292%
Saturday5294%
Sunday5296%

Why it was late

Airline (crew, maintenance, ops) 71%Severe weather 28%Air traffic & airport (NAS) 1%

All flights LAX → RNO · Connecting off DL 4099? Check the risk

DL 4099: RNO → LAX

Scheduled to leave Reno at 10:34 a.m. local time, operated by SkyWest as OO 4099. Over the past year it arrived on time 92% of the time (365 flights), in line with other DL flights on the route at that hour (94%). Last seen in the data Aug 31, 2026.

Month by month

40%70%100%Sep 2025: 97% on time (30 flights)97SepOct 2025: 81% on time (31 flights)81OctNov 2025: 87% on time (30 flights)87NovDec 2025: 84% on time (31 flights)84DecJan 2026: 90% on time (31 flights)90JanFeb 2026: 79% on time (28 flights)79FebMar 2026: 100% on time (31 flights)100MarApr 2026: 97% on time (30 flights)97AprMay 2026: 90% on time (31 flights)90MayJun 2026: 100% on time (30 flights)100JunJul 2026: 97% on time (31 flights)97JulAug 2026: 97% on time (31 flights)97Aug

By day of week

DayFlightsOn time
Monday5396%
Tuesday5290%
Wednesday5288%
Thursday5292%
Friday5290%
Saturday5288%
Sunday5294%

Why it was late

Airline (crew, maintenance, ops) 59%Severe weather 24%Air traffic & airport (NAS) 16%

All flights RNO → LAX · Connecting off DL 4099? Check the risk

Questions

How often is DL 4099 from LAX to RNO late?

Delta Air Lines 4099 from Los Angeles, CA to Reno, NV arrived 15 or more minutes late, was diverted or was cancelled on 5% of 365 scheduled flights between September 2025 and August 2026. 0.5% were cancelled.

How often is DL 4099 from RNO to LAX late?

Delta Air Lines 4099 from Reno, NV to Los Angeles, CA arrived 15 or more minutes late, was diverted or was cancelled on 8% of 365 scheduled flights between September 2025 and August 2026. 0.5% 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 Delta Air Lines for today's flight. Method.