About 1 in 4 DL 1780 flights from Boston arrived 15+ minutes late, diverted or cancelled over the past year (24%); 1.1% were cancelled. The typical flight landed 4 minutes early.
DL 1780: BOS → SJU
Scheduled to leave Boston at 8:05 a.m. local time. Over the past year it arrived on time 76% of the time (365 flights), in line with other DL flights on the route at that hour (76%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 53 | 72% |
| Tuesday | 52 | 75% |
| Wednesday | 52 | 75% |
| Thursday | 52 | 69% |
| Friday | 52 | 83% |
| Saturday | 52 | 81% |
| Sunday | 52 | 75% |
Why it was late
All flights BOS → SJU · Connecting off DL 1780? Check the risk
DL 1780: SJU → BOS
Scheduled to leave San Juan at 2:25 p.m. local time. Over the past year it arrived on time 78% of the time (324 flights), in line with other DL flights on the route at that hour (79%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 48 | 75% |
| Tuesday | 47 | 77% |
| Wednesday | 47 | 74% |
| Thursday | 46 | 78% |
| Friday | 46 | 87% |
| Saturday | 45 | 87% |
| Sunday | 45 | 69% |
Why it was late
All flights SJU → BOS · Connecting off DL 1780? Check the risk
Questions
How often is DL 1780 from BOS to SJU late?
Delta Air Lines 1780 from Boston, MA to San Juan, PR arrived 15 or more minutes late, was diverted or was cancelled on 24% of 365 scheduled flights between September 2025 and August 2026. 1.1% were cancelled.
How often is DL 1780 from SJU to BOS late?
Delta Air Lines 1780 from San Juan, PR to Boston, MA arrived 15 or more minutes late, was diverted or was cancelled on 22% of 324 scheduled flights between September 2025 and August 2026. 0.9% 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.