Flight number record

DL 479

Delta Air Lines · Boston to Los Angeles

Route: BOS → LAX
Departs: 06:15
Flights: 363
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 479, check with Delta Air Lines.

DL 479 lands a B, 2 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 363 flights, with a median arrival 4 minutes early.

On time

79.5%

Arrivals under 15 minutes late, of 356 completed flights

Avg delay

65 min

Across delayed arrivals only, not all flights

Cancelled

1.93%

National rate is 1.81%

1 hour+ late

6.2%

National rate is 8.1%

These figures cover 363 flights between July 2025 and June 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.

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 111 of 363 flights, with 07:30 (96 flights) and 06:20 (56 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 06:15111 flights30.6%
Departs 07:3096 flights26.4%
Departs 06:2056 flights15.4%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

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 10 points worse at 79.5%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

DL 479 next to BOS to LAX

Every carrier on BOS to LAX combined arrived on time 74.9% of the time across 4,713 flights, so DL 479 is 5 points ahead of it. Delta flew 1,228 flights on the same city pair under all its flight numbers, including this one, and those ran 75.2% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 2 points.

DL 479 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 479thin sample	363	79.5%	65 min	1.93%	B
All Delta Air Lines on BOS–LAX	1,228	75.2%	76 min	1.71%	B
All carriers on BOS–LAX	4,713	74.9%	76 min	1.42%	C
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	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 91.3% on time and its weakest Jan–Mar 2026 at 70.9%, a swing of 20 points on roughly 91 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 202592 flights91.3%
Oct–Dec 202592 flights77.8%
Jan–Mar 202690 flights70.9%
Apr–Jun 202689 flights77.3%

Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, DL 479 did best on Sunday at 88.5% on time and worst on Wednesday at 73.1%. Each day rests on about 52 flights, so a gap of 15 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 479 runs late

One category carries most of the weight here. Carrier accounts for 45% of the 4,766 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Carrier
45%
National Airspace System
28%
Late-arriving aircraft
26%
Extreme weather
1%

The largest share of delay minutes, 45%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 2,158 of the 4,766 delay minutes reported here. The split is drawn from 4,766 delay minutes reported on DL 479.

Cancellations sit at 1.93% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and routes

What a delay on this flight costs

6.2% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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 79.5% on time with 1.93% cancelled over 363 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures