About 1 in 5 DL 977 flights from Boston arrived 15+ minutes late, diverted or cancelled over the past year (21%); 2.1% were cancelled. The typical flight landed 2 minutes early.
DL 977: BOS → SFO
Scheduled to leave Boston at 7:40 a.m. local time. Over the past year it arrived on time 79% of the time (234 flights), in line with other DL flights on the route at that hour (80%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 37 | 73% |
| Tuesday | 36 | 72% |
| Wednesday | 36 | 81% |
| Thursday | 36 | 89% |
| Friday | 36 | 72% |
| Saturday | 20 | 75% |
| Sunday | 33 | 88% |
Why it was late
All flights BOS → SFO · Connecting off DL 977? Check the risk
DL 977: SFO → BOS
Scheduled to leave San Francisco at 1:00 p.m. local time. Over the past year it arrived on time 56% of the time (230 flights), worse than other DL flights on the route at that hour (59%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 37 | 46% |
| Tuesday | 36 | 58% |
| Wednesday | 34 | 62% |
| Thursday | 34 | 56% |
| Friday | 36 | 58% |
| Saturday | 20 | 55% |
| Sunday | 33 | 55% |
Why it was late
All flights SFO → BOS · Connecting off DL 977? Check the risk
Questions
How often is DL 977 from BOS to SFO late?
Delta Air Lines 977 from Boston, MA to San Francisco, CA arrived 15 or more minutes late, was diverted or was cancelled on 21% of 234 scheduled flights between September 2025 and August 2026. 2.1% were cancelled.
How often is DL 977 from SFO to BOS late?
Delta Air Lines 977 from San Francisco, CA to Boston, MA arrived 15 or more minutes late, was diverted or was cancelled on 44% of 230 scheduled flights between September 2025 and August 2026. 1.7% 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.