Flight Reliability
DL 1861 · Delta Air Lines
Atlanta → San Juan (ATL–SJU)
55
A Little Dicey
WanderNerd Reliability Score
- 62%
- Arrive within 15 minutes
- 22 min
- Average arrival delay
- 2.0%
- Cancelled
- 4 min
- Median arrival delay
Based on 349 historical flights. Data through May 2026.
What the data says
Thursdays have been rough.
DL 1861 arrived on time 69% of the time on Mondays and just 52% on Thursdays. That gap is worth planning around.
Lagging the ATL–SJU route.
DL 1861 arrived on time 62% of the time, versus 70% across the ATL–SJU route.
Well behind the Delta Air Lines network.
DL 1861 arrived on time 62% of the time, versus 81% across the Delta Air Lines network.
Ticking up lately.
DL 1861 arrived on time 64% of the time over the last three months in the data, compared with 60% in the three months before that.
The breakdown
- Mon69%(49 flights)
- Tue63%(48 flights)
- Wed69%(49 flights)
- Thu52%(50 flights)
- Fri67%(48 flights)
- Sat60%(48 flights)
- Sun55%(49 flights)
73%
May
Jun 45% → May 73% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 45% | 29 |
| July 2025 | 47% | 30 |
| August 2025 | 73% | 30 |
| September 2025 | 63% | 30 |
| October 2025 | 71% | 31 |
| November 2025 | 72% | 29 |
| December 2025 | 50% | 30 |
| January 2026 | 76% | 25 |
| February 2026 | 53% | 17 |
| March 2026 | 60% | 30 |
| April 2026 | 60% | 30 |
| May 2026 | 73% | 30 |
- Departures on time
- 64%
- Diverted
- 0.3%
- Flights flown
- 341
- Months covered
- 12
Same route, other flights
Keep nerding
Based on 349 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.