Flight number record
DL 479
Delta Air Lines · Boston to Los Angeles
- Route
- BOS → LAX
- Departs
- 06:15
- Flights
- 363
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 479, check with Delta Air Lines.
DL 479 lands a B, about a point better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 363 flights, with a median arrival 4 minutes early.
Key figures
On time
78.4%
Arrivals under 15 minutes late, of 356 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
1.93%
National rate is 1.89%
1 hour+ late
7.0%
National rate is 8.3%
These figures cover 363 flights between September 2025 and August 2026. The median arrival is 4 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Schedule
When DL 479 flies
DL 479 flies BOS to LAX without a single fixed slot. Its most common scheduled departure was 06:15, used on 99 of 363 flights, with 07:30 (96 flights) and 06:20 (50 flights) next.
- Departs 06:1599 flights27.3%
- Departs 07:3096 flights26.4%
- Departs 06:2050 flights13.8%
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 06:15 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 479 runs 11 points worse at 78.4%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 479 next to BOS to LAX
Every carrier on BOS to LAX combined arrived on time 73.7% of the time across 4,794 flights, so DL 479 is 5 points ahead of it. Delta flew 1,238 flights on the same city pair under all its flight numbers, including this one, and those ran 73.9% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 3 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 479thin sample | 363 | 78.4% | 60 min | 1.93% | B |
| All Delta Air Lines on BOS–LAX | 1,238 | 73.9% | 74 min | 2.18% | C |
| All carriers on BOS–LAX | 4,794 | 73.7% | 79 min | 1.81% | C |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 479 quarter by quarter
DL 479 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Jan–Mar 2026 at 70.9%, a swing of 22 points on roughly 73 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 202530 flights93.3%
- Oct–Dec 202592 flights77.8%
- Jan–Mar 202690 flights70.9%
- Apr–Jun 202689 flights77.3%
- Jul–Sep 202662 flights83.9%
Scale runs 60% to 100%.
By weekday, DL 479 ranged from 71.2% on Wednesday to 82.7% on Sunday. With about 52 flights behind each day, a spread of 12 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late DL 479 runs when it is late
DL 479 often beats the schedule: 97 of 356 completed flights, 27%, arrived 15 minutes or more early. The 77 late arrivals split 32 under half an hour, 20 between 30 and 60 minutes, and 25 an hour or more.
- 15+ min early97 flights27.2%
- Within 15 min182 flights51.1%
- 15–29 min late32 flights9.0%
- 30–59 min late20 flights5.6%
- 1–2 hours late15 flights4.2%
- 2+ hours late10 flights2.8%
Scale runs 0% to 100%.
Share of 356 completed flights by arrival against schedule.
14 of 58 late departures made up the time and arrived on time, 24% of them. In the other direction, 33 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 LAX.
The worst days
Worst days for DL 479
The latest arrival of the period was on 3 January 2026, 4 hours 9 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 3 January 2026 | 4 hours 9 minutes | Carrier |
| 4 June 2026 | 3 hours 33 minutes | Carrier |
| 13 February 2026 | 3 hours 24 minutes | Carrier |
| 8 October 2025 | 3 hours 12 minutes | Carrier |
| 18 August 2026 | 2 hours 54 minutes | Carrier |
Delay causes
Why DL 479 runs late
Carrier accounts for 54% of the 4,605 delay minutes carriers reported here, and the remaining four split what is left.
- 54%Carrier
- 31%National Airspace System
- 14%Late-arriving aircraft
- 1%Extreme weather
The largest share of delay minutes, 54%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,507 of the 4,605 delay minutes reported here. The split is drawn from 4,605 delay minutes reported on DL 479.
Cancellations sit at 1.93% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
7.0% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
At 2,611 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.
Every one of the 363 flights under DL 479 in the data flew BOS to LAX. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 363 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 479
For a booking, read DL 479 as 78.4% on time with 1.93% cancelled over 363 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- BOS to LAX, every carrier and departure
- LAX to BOS, the return direction
- Delta Air Lines 318 on the same route70.8%
- JetBlue Airways 287 on the same route85.1%
- JetBlue Airways 387 on the same route64.5%
- JetBlue Airways 487 on the same route72.3%
- Delta Air Lines 321 on the same route65.8%
- Boston Logan International (BOS) delay statistics
- Los Angeles International (LAX) 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
- Worst months to fly in the US, ranked by the data
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.