About 1 in 5 DL 3956 flights from Seattle arrived 15+ minutes late, diverted or cancelled over the past year (21%); 0.4% were cancelled. The typical flight landed 6 minutes early.
DL 3956: SEA → SJC
Scheduled to leave Seattle at 7:50 p.m. local time, operated by SkyWest as OO 3956. Over the past year it arrived on time 79% of the time (231 flights), better than other DL flights on the route at that hour (71%). Last seen in the data Aug 31, 2026.
Usually Delta Air Lines's last flight of the day from Seattle to San Jose (100% of days). Delta Air Lines's last SEA–SJC flight was cancelled 0.5% of the time, against 0.1% for its earlier ones. If it's cancelled, the next Delta Air Lines flight is usually around 8:30 a.m. the next morning.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 35 | 71% |
| Tuesday | 34 | 88% |
| Wednesday | 34 | 79% |
| Thursday | 34 | 76% |
| Friday | 34 | 71% |
| Saturday | 26 | 88% |
| Sunday | 34 | 79% |
Why it was late
All flights SEA → SJC · Connecting off DL 3956? Check the risk
Questions
How often is DL 3956 from SEA to SJC late?
Delta Air Lines 3956 from Seattle, WA to San Jose, CA arrived 15 or more minutes late, was diverted or was cancelled on 21% of 231 scheduled flights between September 2025 and August 2026. 0.4% 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.