Flight number record

DL 1861

Delta Air Lines · Atlanta to San Juan

Route: ATL → SJU
Departs: 18:45
Flights: 349
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1861, check with Delta Air Lines.

DL 1861 draws a D. Roughly 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 349 flights, with a median arrival 2 minutes late.

The national on-time rate over the same period is 77.6%, so DL 1861 runs 14 points behind the country as a whole. Across a thousand flights that is about 141 extra late arrivals.

On time

63.5%

Arrivals under 15 minutes late, of 342 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

1.72%

National rate is 1.81%

1 hour+ late

10.2%

National rate is 8.1%

These figures cover 349 flights between July 2025 and June 2026. Beyond the headline rate, 10.2% 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 1861 flies

DL 1861 flies ATL to SJU without a single fixed slot. Its most common scheduled departure was 18:45, used on 90 of 349 flights, with 18:30 (56 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 18:4590 flights25.8%
Departs 18:3056 flights16.0%

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 18:45 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and DL 1861 runs 5 points worse at 63.5%. 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 1861 next to ATL to SJU

Every carrier on ATL to SJU combined arrived on time 70.5% of the time across 2,130 flights, so DL 1861 is 7 points behind it. Delta flew 1,636 flights on the same city pair under all its flight numbers, including this one, and those ran 75.8% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 18 points.

DL 1861 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1861thin sample	349	63.5%	58 min	1.72%	D
All Delta Air Lines on ATL–SJU	1,636	75.8%	51 min	0.92%	B+
All carriers on ATL–SJU	2,130	70.5%	58 min	1.27%	C
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1861 quarter by quarter

Quarter by quarter DL 1861 held fairly steady: 60.0% in Jul–Sep 2025, 62.2% in Oct–Dec 2025, 62.5% in Jan–Mar 2026 and 68.9% 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 flights60.0%
Oct–Dec 202592 flights62.2%
Jan–Mar 202674 flights62.5%
Apr–Jun 202691 flights68.9%

Scale runs 50% to 75%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1861 did best on Wednesday at 71.4% on time and worst on Sunday at 52.1%. Each day rests on about 50 flights, so a gap of 19 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 1861 runs late

One category carries most of the weight here. Carrier accounts for 60% of the 7,279 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
60%
Late-arriving aircraft
22%
National Airspace System
13%
Extreme weather
5%
Security
0%

The largest share of delay minutes, 60%, 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 4,381 of the 7,279 delay minutes reported here. The split is drawn from 7,279 delay minutes reported on DL 1861.

Cancellations sit at 1.72% against a national 1.81%, which is ordinary. Diversions add another 0.29%.

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. 10.2% 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.

At 1,547 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 349 flights under DL 1861 in the data flew ATL to SJU. 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. 349 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 1861

For a booking, DL 1861 is one of the weaker ways to fly ATL to SJU: 7 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.

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