Flight number record
DL 1655
Delta Air Lines · Boston to San Francisco
- Route
- BOS → SFO
- Departs
- 17:05
- Flights
- 337
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1655, check with Delta Air Lines.
DL 1655 draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 337 flights, with a median arrival 1 minute late.
The national on-time rate over the same period is 77.3%, so DL 1655 runs 11 points behind the country as a whole. Across a thousand flights that is about 112 extra late arrivals.
Key figures
On time
66.1%
Arrivals under 15 minutes late, of 330 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
1.78%
National rate is 1.89%
1 hour+ late
10.0%
National rate is 8.3%
These figures cover 337 flights between September 2025 and August 2026. Beyond the headline rate, 10.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 1655 flies
DL 1655 flies BOS to SFO without a single fixed slot. Its most common scheduled departure was 17:05, used on 63 of 337 flights, with 16:55 (63 flights) and 17:40 (38 flights) next.
- Departs 17:0563 flights18.7%
- Departs 16:5563 flights18.7%
- Departs 17:4038 flights11.3%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 17:05 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and DL 1655 runs level with that at 66.1%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
DL 1655 next to BOS to SFO
Every carrier on BOS to SFO combined arrived on time 69.2% of the time across 4,817 flights, so DL 1655 is 3 points behind it. Delta flew 945 flights on the same city pair under all its flight numbers, including this one, and those ran 69.0% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 15 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1655thin sample | 337 | 66.1% | 61 min | 1.78% | C |
| All Delta Air Lines on BOS–SFO | 945 | 69.0% | 63 min | 1.59% | C |
| All carriers on BOS–SFO | 4,817 | 69.2% | 66 min | 1.58% | C |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1655 quarter by quarter
DL 1655 did not run the same all year. Its best quarter was Oct–Dec 2025 at 78.8% on time and its weakest Apr–Jun 2026 at 41.8%, a swing of 37 points on roughly 84 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202529 flights—
- Oct–Dec 202569 flights78.8%
- Jan–Mar 202686 flights77.1%
- Apr–Jun 202691 flights41.8%
- Jul–Sep 202662 flights72.1%
Scale runs 35% to 85%. Rows with fewer than 30 flights show a dash.
By weekday, DL 1655 did best on Wednesday at 74.5% on time and worst on Thursday at 59.6%. Each day rests on about 48 flights, so a gap of 15 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1655 runs when it is late
DL 1655 often beats the schedule: 93 of 330 completed flights, 28%, arrived 15 minutes or more early. The 112 late arrivals split 41 under half an hour, 38 between 30 and 60 minutes, and 33 an hour or more.
- 15+ min early93 flights28.2%
- Within 15 min125 flights37.9%
- 15–29 min late41 flights12.4%
- 30–59 min late38 flights11.5%
- 1–2 hours late22 flights6.7%
- 2+ hours late11 flights3.3%
Scale runs 0% to 100%.
Share of 330 completed flights by arrival against schedule.
25 of 98 late departures made up the time and arrived on time, 26% of them. In the other direction, 39 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SFO.
The worst days
Worst days for DL 1655
The latest arrival of the period was on 14 October 2025, 16 hours 17 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 14 October 2025 | 16 hours 17 minutes | National Airspace System |
| 23 August 2026 | 5 hours 40 minutes | Carrier |
| 1 April 2026 | 3 hours 5 minutes | Carrier |
| 20 April 2026 | 3 hours | National Airspace System |
| 19 May 2026 | 2 hours 47 minutes | National Airspace System |
Delay causes
Why DL 1655 runs late
National Airspace System accounts for 65% of the 6,857 delay minutes carriers reported here, and the remaining four split what is left.
- 65%National Airspace System
- 21%Carrier
- 14%Late-arriving aircraft
- 1%Extreme weather
65% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 4,446 minutes out of 6,857, against a national NAS share of 21%. The split is drawn from 6,857 delay minutes reported on DL 1655.
Cancellations sit at 1.78% against a national 1.89%, which is ordinary. Diversions add another 0.30%.
Connections and routes
What a delay on this flight costs
10.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
At 2,704 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The same number turns up on one other city pair in the data, including SFO to BOS (171), but none flew often enough under DL 1655 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to SFO only.
One caution: this is a thin sample. 337 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking DL 1655
For a booking, read DL 1655 as 66.1% on time with 1.78% cancelled over 337 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- BOS to SFO, every carrier and departure
- SFO to BOS, the return direction
- JetBlue Airways 733 on the same route55.9%
- United Airlines 2400 on the same route51.1%
- United Airlines 2441 on the same route84.4%
- JetBlue Airways 333 on the same route54.3%
- United Airlines 1074 on the same route77.8%
- Boston Logan International (BOS) delay statistics
- San Francisco International (SFO) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- The best time of day to fly, according to 7.05 million flight records
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.