About 1 in 9 UA 1257 flights from Miami arrived 15+ minutes late, diverted or cancelled over the past year (11%); 0.6% were cancelled. The typical flight landed 14 minutes early.
UA 1257: MIA → SFO
Scheduled to leave Miami at 8:00 a.m. local time. Over the past year it arrived on time 89% of the time (158 flights), in line with other UA flights on the route at that hour (88%). Last seen in the data Aug 10, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 23 | 91% |
| Tuesday | 22 | 82% |
| Wednesday | 22 | 95% |
| Thursday | 23 | 91% |
| Friday | 23 | 83% |
| Saturday | 23 | 87% |
| Sunday | 22 | 91% |
Why it was late
All flights MIA → SFO · Connecting off UA 1257? Check the risk
Questions
How often is UA 1257 from MIA to SFO late?
United Airlines 1257 from Miami, FL to San Francisco, CA arrived 15 or more minutes late, was diverted or was cancelled on 11% of 158 scheduled flights between September 2025 and August 2026. 0.6% 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.