About 1 in 7 UA 1678 flights from San Francisco arrived 15+ minutes late, diverted or cancelled over the past year (14%); 0.5% were cancelled. The typical flight landed 14 minutes early.
UA 1678: SFO → DCA
Scheduled to leave San Francisco at 8:20 a.m. local time. Over the past year it arrived on time 87% of the time (363 flights), in line with other UA flights on the route at that hour (87%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 53 | 83% |
| Tuesday | 52 | 94% |
| Wednesday | 51 | 84% |
| Thursday | 52 | 81% |
| Friday | 52 | 79% |
| Saturday | 51 | 92% |
| Sunday | 52 | 92% |
Why it was late
All flights SFO → DCA · Connecting off UA 1678? Check the risk
UA 1678: DCA → IAH
Scheduled to leave Washington at 7:59 p.m. local time. Over the past year it arrived on time 70% of the time (133 flights), worse than other UA flights on the route at that hour (80%). Last seen in the data Aug 31, 2026.
Usually United Airlines's last flight of the day from Washington to Houston (100% of days). United Airlines's last DCA–IAH flight was cancelled 0.8% of the time, against 0.8% for its earlier ones. If it's cancelled, the next United Airlines flight is usually around 6:00 a.m. the next morning.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 22 | 73% |
| Tuesday | 21 | 57% |
| Wednesday | 21 | 81% |
| Thursday | 23 | 78% |
| Friday | 23 | 70% |
| Sunday | 23 | 61% |
Why it was late
All flights DCA → IAH · Connecting off UA 1678? Check the risk
Questions
How often is UA 1678 from SFO to DCA late?
United Airlines 1678 from San Francisco, CA to Washington, DC arrived 15 or more minutes late, was diverted or was cancelled on 14% of 363 scheduled flights between September 2025 and August 2026. 0.5% were cancelled.
How often is UA 1678 from DCA to IAH late?
United Airlines 1678 from Washington, DC to Houston, TX arrived 15 or more minutes late, was diverted or was cancelled on 30% of 133 scheduled flights between September 2025 and August 2026. 0.8% 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.