About 1 in 10 UA 2309 flights from Denver arrived 15+ minutes late, diverted or cancelled over the past year (10%); 0.3% were cancelled. The typical flight landed 13 minutes early.
UA 2309: DEN → SAN
Scheduled to leave Denver at 7:45 a.m. local time. Over the past year it arrived on time 90% of the time (343 flights), in line with other UA flights on the route at that hour (91%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 50 | 94% |
| Tuesday | 49 | 96% |
| Wednesday | 49 | 94% |
| Thursday | 49 | 86% |
| Friday | 48 | 90% |
| Saturday | 49 | 90% |
| Sunday | 49 | 84% |
Why it was late
All flights DEN → SAN · Connecting off UA 2309? Check the risk
UA 2309: SAN → SFO
Scheduled to leave San Diego at 11:01 a.m. local time. Over the past year it arrived on time 63% of the time (205 flights), better than other UA flights on the route at that hour (60%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 31 | 55% |
| Tuesday | 28 | 61% |
| Wednesday | 28 | 54% |
| Thursday | 30 | 63% |
| Friday | 30 | 57% |
| Saturday | 27 | 78% |
| Sunday | 31 | 74% |
Why it was late
All flights SAN → SFO · Connecting off UA 2309? Check the risk
Questions
How often is UA 2309 from DEN to SAN late?
United Airlines 2309 from Denver, CO to San Diego, CA arrived 15 or more minutes late, was diverted or was cancelled on 10% of 343 scheduled flights between September 2025 and August 2026. 0.3% were cancelled.
How often is UA 2309 from SAN to SFO late?
United Airlines 2309 from San Diego, CA to San Francisco, CA arrived 15 or more minutes late, was diverted or was cancelled on 37% of 205 scheduled flights between September 2025 and August 2026. 0.0% 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 United Airlines for today's flight. Method.