Flight number record

DL 1257

Delta Air Lines · Atlanta to Baltimore

Route: ATL → BWI
Departs: 18:59
Flights: 303
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1257, check with Delta Air Lines.

DL 1257 sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 303 flights, with a median arrival right on schedule.

The national on-time rate over the same period is 77.6%, so DL 1257 runs 7 points behind the country as a whole. Across a thousand flights that is about 65 extra late arrivals.

On time

71.1%

Arrivals under 15 minutes late, of 298 completed flights

Avg delay

70 min

Across delayed arrivals only, not all flights

Cancelled

1.32%

National rate is 1.81%

1 hour+ late

12.8%

National rate is 8.1%

These figures cover 303 flights between July 2025 and June 2026. Beyond the headline rate, 12.8% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Schedule

When DL 1257 flies

DL 1257 flies ATL to BWI without a single fixed slot. Its most common scheduled departure was 18:59, used on 75 of 303 flights, with 20:27 (36 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 18:5975 flights24.8%
Departs 20:2736 flights11.9%

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 18:59 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and DL 1257 runs 3 points better at 71.1%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

DL 1257 next to ATL to BWI

Every carrier on ATL to BWI combined arrived on time 75.6% of the time across 5,414 flights, so DL 1257 is 5 points behind it. Delta flew 2,824 flights on the same city pair under all its flight numbers, including this one, and those ran 78.3% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 11 points.

DL 1257 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1257thin sample	303	71.1%	70 min	1.32%	C
All Delta Air Lines on ATL–BWI	2,824	78.3%	59 min	1.95%	B
All carriers on ATL–BWI	5,414	75.6%	63 min	1.98%	B
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1257 quarter by quarter

DL 1257 did not run the same all year. Its best quarter was Oct–Dec 2025 at 82.9% on time and its weakest Jan–Mar 2026 at 55.3%, a swing of 28 points on roughly 76 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 202590 flights63.3%
Oct–Dec 202577 flights82.9%
Jan–Mar 202649 flights55.3%
Apr–Jun 202687 flights77.6%

Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1257 did best on Wednesday at 77.5% on time and worst on Friday at 65.1%. Each day rests on about 43 flights, so a gap of 12 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 1257 runs late

One category carries most of the weight here. Carrier accounts for 48% of the 6,052 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
48%
National Airspace System
22%
Late-arriving aircraft
18%
Extreme weather
12%

Extreme weather accounts for 12% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 1.9 times the usual weather exposure. The split is drawn from 6,052 delay minutes reported on DL 1257.

Cancellations sit at 1.32% against a national 1.81%, which is ordinary. Diversions add another 0.33%.

Connections and routes

What a delay on this flight costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 12.8% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

The 577 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.

The same number turns up on one other city pair in the data, including LAS to SEA (24), but none flew often enough under DL 1257 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ATL to BWI only.

One caution: this is a thin sample. 303 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 1257

For a booking, DL 1257 is a flight to put a long connection behind. 12.8% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.

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