Flight profile · United Airlines
UA1678
San Francisco (SFO) to Washington (DCA) · scheduled 8:35 AM – 4:52 PM
How UA1678 performs
619 operations, December 2024 – August 2026.
Between its first and last recorded date on SFO → DCA, UA1678 averaged about one operation a day or more (619 in 621 days, cancelled ones included).
UA1678 arrived on time 88.2% of the time, against 81.7% for all SFO → DCA flights, so this departure is 6.5 percentage points better than the route as a whole. Against United Airlines’ own flights on this route it is 5.3 points better.
Source: US DOT Bureau of Transportation Statistics · 619 operations, December 2024 – August 2026 · If UA1678 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where UA1678 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
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Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| UA1678 | 88.2% | 0.65% | -11 min | 3.0% | 619 |
| United Airlines on SFO → DCA | 82.9% | 0.58% | -10 min | 5.3% | 1,720 |
| All SFO → DCA flights | 81.7% | 0.52% | -9 min | 5.2% | 2,871 |
UA1678 cancelled 4 of 619 operations (0.65%), close to the 0.52% for SFO → DCA.
3.0% of UA1678’s arrivals were an hour or more late, against 5.2% across SFO → DCA, so the long delays are less common on this number than on the route.
Source: FlyerIntel analysis of US DOT BTS data · December 2024 – August 2026
Why UA1678 runs late
Where US DOT attributed the delay minutes on this flight.
airspace and airport capacity, including weather-driven flow control
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for UA1678 on SFO → DCA. Only delays of 15 minutes or more are attributed. What the five causes mean
Source: US DOT Bureau of Transportation Statistics · Data covering December 2024 – August 2026
Does a late aircraft delay this flight?
How often the plane that flies UA1678 comes in late, and what that does to the departure.
The aircraft flying UA1678 came in 15 or more minutes late on 12% of the departures where its previous flight is known. There are not enough departures in both groups to say how the flight left after a late one and after an on-time one.
Matched by tail number to the aircraft’s previous flight into SFO: 521 of 615 departures. Unknown, cancelled or diverted inbounds and gaps over 12 hours are left out.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late |
|---|---|
| UA1678 | 12% |
| Network, same turn | 17% |
89 scheduled minutes is enough to clean and board when the aircraft is on time, with little to spare when it is not.
The network row is every flight with a scheduled turn of 60 to 89 minutes. How often UA1678’s aircraft landed 15 or more minutes late is lower than the network’s. There are not enough departures in both groups to compare how it left.
Source: US DOT Bureau of Transportation Statistics · Data covering December 2024 – August 2026
From pushback to gate
When it leaves SFO late, does that still matter by the time it reaches DCA?
UA1678 pushes back an average of 0.3 minutes late and reaches the gate at DCA an average of 6.4 minutes early. The 6.7 minutes between those two figures are slack the published schedule already carries, so on average a late pushback on this flight is made up before the gate. It spends 26.7 minutes on the taxiways at SFO, 3.5 minutes longer than a typical SFO departure in the same hour.
On arrival at DCA, UA1678 spends 7.6 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is about what any arrival at DCA spends on the ground before reaching the gate.
Taxi-out is gate to wheels up and sits inside the scheduled block; the hourly comparison is 40,001 SFO departures. Taxi-in is landing to gate, set against 447,280 arrivals at DCA. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · December 2024 – August 2026
The hour it leaves SFO
UA1678 has one departure time, 8:35 AM, so this is what that hour at SFO is worth.
On-time arrival rate. 40,001 departures from SFO are scheduled in the 8 AM–9 AM hour over the period, against 449,339 across the whole day.
UA1678 is scheduled out of SFO at 8:35 AM, in the 8 AM–9 AM bank. Departures from SFO in that hour arrive on time 85.1% of the time against 78.3% across the airport’s whole day — the slot alone is worth 6.8 points better before anything about this particular flight is considered.
Both airport figures cover every destination from SFO, so they describe the slot, not this journey; the route comparison is above. Why the hour matters.
Source: FlyerIntel analysis of US DOT BTS data · December 2024 – August 2026 · Hours below 120 departures are not scored.
Other routes UA1678 has flown
Carriers reassign flight numbers. UA1678 also served these 20 other city pairs in the period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| DCA→IAH Washington to Houston | March 5, 2026 – August 31, 2026 | 133 | 70.5% |
| PHX→SFO Phoenix to San Francisco | December 2, 2025 – March 4, 2026 | 78 | — |
| EWR→LAS Newark to Las Vegas | December 3–18, 2024 | 16 | — |
| ORD→BTV Chicago to Burlington | October 27, 2024 – December 2, 2024 | 37 | — |
| MFR→SFO Medford to San Francisco | March 7, 2024 – October 26, 2024 | 91 | 95.5% |
| SFO→TPA San Francisco to Tampa | August 19, 2024 – September 25, 2024 | 38 | — |
| ORD→DCA Chicago to Washington | June 27, 2024 – August 18, 2024 | 45 | — |
| CHS→ORD Charleston to Chicago | August 2–18, 2024 | 10 | — |
| SFO→ANC San Francisco to Anchorage | June 29, 2024 – August 17, 2024 | 8 | — |
| SFO→BUR San Francisco to Burbank | June 1–26, 2024 | 26 | — |
| SFO→IAD San Francisco to Washington | April 1, 2024 – May 22, 2024 | 52 | — |
| SFO→BOS San Francisco to Boston | February 15, 2024 – March 30, 2024 | 45 | — |
| MSP→ORD Minneapolis to Chicago | January 9, 2024 – February 14, 2024 | 37 | — |
| SFO→RNO San Francisco to Reno | December 21, 2023 – January 8, 2024 | 17 | — |
| LAX→SFO Los Angeles to San Francisco | November 28, 2023 – December 20, 2023 | 23 | — |
| SFO→BWI San Francisco to Baltimore | October 29, 2023 – November 27, 2023 | 30 | — |
| EWR→PWM Newark to Portland | October 1–27, 2023 | 20 | — |
| IAH→AUS Houston to Austin | October 23, 2023 | 1 | — |
| LAX→DEN Los Angeles to Denver | September 29–30, 2023 | 2 | — |
| DCA→ORD Washington to Chicago | July 1, 2023 – September 28, 2023 | 89 | — |
The figures above describe only SFO → DCA, the route UA1678 flies now.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
20 min late
against a median of 11 min early
Percentiles over 619 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering December 2024 – August 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| UA1678 this flight | United Airlines | 88.2% | 11 min early | 619 |
| AS8 | Alaska Airlines | 80.0% | 8 min early | 1,151 |
Among all 2 departures on this route with at least 600 operations, UA1678 has the highest on-time rate. Every departure here has at least 600 operations; the other rows are the most punctual on the route, not all of them.
Data and methodology
Calculated by FlyerIntel from 619 records of UA1678 operating SFO → DCA, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule; cancelled and diverted flights are reported separately, not in the on-time rate.
Full methodology · Data sources · Report a problem
Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air
Analysis last recomputed