Flight number record

DL 350

Delta Air Lines · Atlanta to Boston

Route: ATL → BOS
Departs: 12:40
Flights: 348
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 350, check with Delta Air Lines.

DL 350 sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land about 50 minutes behind schedule. That rests on 348 flights, with a median arrival 4 minutes early.

On time

75.5%

Arrivals under 15 minutes late, of 339 completed flights

Avg delay

50 min

Across delayed arrivals only, not all flights

Cancelled

2.30%

National rate is 1.81%

1 hour+ late

6.5%

National rate is 8.1%

These figures cover 348 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 350 flies

DL 350 flies ATL to BOS without a single fixed slot. Its most common scheduled departure was 12:40, used on 42 of 348 flights, with 12:45 (36 flights) and 12:28 (35 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 12:4042 flights12.1%
Departs 12:4536 flights10.3%
Departs 12:2835 flights10.1%

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 12:40 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and DL 350 runs 3 points worse at 75.5%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

DL 350 next to ATL to BOS

Every carrier on ATL to BOS combined arrived on time 74.5% of the time across 4,935 flights, so DL 350 is about level with it. Delta flew 3,666 flights on the same city pair under all its flight numbers, including this one, and those ran 76.2% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 6 points.

DL 350 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 350thin sample	348	75.5%	50 min	2.30%	B
All Delta Air Lines on ATL–BOS	3,666	76.2%	59 min	1.72%	B
All carriers on ATL–BOS	4,935	74.5%	63 min	1.95%	C
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 350 quarter by quarter

Quarter by quarter DL 350 held fairly steady: 71.4% in Jul–Sep 2025, 74.2% in Oct–Dec 2025, 80.8% in Jan–Mar 2026 and 76.5% in Apr–Jun 2026. A spread of 9 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights71.4%
Oct–Dec 202590 flights74.2%
Jan–Mar 202684 flights80.8%
Apr–Jun 202682 flights76.5%

Scale runs 65% to 85%. Rows with fewer than 30 flights show a dash.

By weekday, DL 350 did best on Saturday at 81.6% on time and worst on Monday at 69.6%. Each day rests on about 50 flights, so a gap of 12 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 350 runs late

One category carries most of the weight here. National Airspace System accounts for 56% of the 4,152 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.

National Airspace System
56%
Carrier
34%
Late-arriving aircraft
8%
Extreme weather
2%

The largest share of delay minutes, 34%, 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 1,416 of the 4,152 delay minutes reported here. The split is drawn from 4,152 delay minutes reported on DL 350.

Cancellations sit at 2.30% against a national 1.81%, which is ordinary. Diversions add another 0.29%.

Connections and routes

What a delay on this flight costs

6.5% 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 50 minutes, which a normal layover absorbs.

The 946 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

Every one of the 348 flights under DL 350 in the data flew ATL to BOS. 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. 348 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 350

For a booking, read DL 350 as 75.5% on time with 2.30% cancelled over 348 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