Flight number record
DL 1861
Delta Air Lines · Atlanta to San Juan
- Route
- ATL → SJU
- Departs
- 18:45
- Flights
- 349
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1861, check with Delta Air Lines.
DL 1861 draws a C. About 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 1 minute late.
The national on-time rate over the same period is 77.3%, so DL 1861 runs 11 points behind the country as a whole. Across a thousand flights that is about 113 extra late arrivals.
Key figures
On time
66.0%
Arrivals under 15 minutes late, of 344 completed flights
Avg delay
58 min
Across delayed arrivals only, not all flights
Cancelled
1.43%
National rate is 1.89%
1 hour+ late
10.2%
National rate is 8.3%
These figures cover 349 flights between September 2025 and August 2026. Beyond the headline rate, 10.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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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 117 of 349 flights, with 18:30 (35 flights) next.
- Departs 18:45117 flights33.5%
- Departs 18:3035 flights10.0%
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 18:45 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and DL 1861 runs 2 points worse at 66.0%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
DL 1861 next to ATL to SJU
Every carrier on ATL to SJU combined arrived on time 71.6% of the time across 2,101 flights, so DL 1861 is 6 points behind it. Delta flew 1,638 flights on the same city pair under all its flight numbers, including this one, and those ran 76.9% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 15 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1861thin sample | 349 | 66.0% | 58 min | 1.43% | C |
| All Delta Air Lines on ATL–SJU | 1,638 | 76.9% | 53 min | 0.85% | B+ |
| All carriers on ATL–SJU | 2,101 | 71.6% | 58 min | 1.29% | C |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1861 quarter by quarter
DL 1861 did not run the same all year. Its best quarter was Jul–Sep 2026 at 72.6% on time and its weakest Oct–Dec 2025 at 62.2%, a swing of 10 points on roughly 70 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 flights63.3%
- Oct–Dec 202592 flights62.2%
- Jan–Mar 202674 flights62.5%
- Apr–Jun 202691 flights68.9%
- Jul–Sep 202662 flights72.6%
Scale runs 55% to 80%.
By weekday, DL 1861 did best on Tuesday at 72.9% on time and worst on Sunday at 51.0%. Each day rests on about 50 flights, so a gap of 22 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1861 runs when it is late
The 117 late arrivals split 43 under half an hour, 39 between 30 and 60 minutes, and 35 an hour or more.
- 15+ min early39 flights11.3%
- Within 15 min188 flights54.7%
- 15–29 min late43 flights12.5%
- 30–59 min late39 flights11.3%
- 1–2 hours late27 flights7.8%
- 2+ hours late8 flights2.3%
Scale runs 0% to 100%.
Share of 344 completed flights by arrival against schedule.
14 of 115 late departures made up the time and arrived on time, 12% of them. 16 flights left on time and still arrived late.
The worst days
Worst days for DL 1861
The latest arrival of the period was on 6 March 2026, 12 hours 30 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 6 March 2026 | 12 hours 30 minutes | Carrier |
| 5 January 2026 | 3 hours 32 minutes | Carrier |
| 14 September 2025 | 3 hours 4 minutes | Carrier |
| 24 February 2026 | 2 hours 50 minutes | Carrier |
| 10 October 2025 | 2 hours 45 minutes | Late-arriving aircraft |
Delay causes
Why DL 1861 runs late
Carrier accounts for 63% of the 6,822 delay minutes carriers reported here, and the remaining four split what is left.
- 63%Carrier
- 21%Late-arriving aircraft
- 12%National Airspace System
- 4%Extreme weather
- 0%Security
The largest share of delay minutes, 63%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,266 of the 6,822 delay minutes reported here. The split is drawn from 6,822 delay minutes reported on DL 1861.
Cancellations sit at 1.43% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
10.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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: 6 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.
Related
Where to go next
- ATL to SJU, every carrier and departure
- SJU to ATL, the return direction
- Delta Air Lines 1946 on the same route81.8%
- Delta Air Lines 1882 on the same route77.1%
- Frontier Airlines 2082 on the same route57.7%
- Delta Air Lines 1757 on the same route88.4%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Luis Munoz Marin International (SJU) 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
- How often a connection fails at the major US hubs
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.