Flight Reliability
DL 1859 · Delta Air Lines
New York → San Juan (JFK–SJU)
70
Usually Fine
WanderNerd Reliability Score
- 70%
- Arrive within 15 minutes
- 10 min
- Average arrival delay
- 1.9%
- Cancelled
- 2 min early
- Median arrival delay
Based on 359 historical flights. Data through May 2026.
What the data says
Thursdays have been rough.
DL 1859 arrived on time 80% of the time on Fridays and just 54% on Thursdays. That gap is worth planning around.
Lagging the Delta Air Lines network.
DL 1859 arrived on time 70% of the time, versus 81% across the Delta Air Lines network.
Trending in the right direction.
DL 1859 arrived on time 81% of the time over the last three months in the data, compared with 62% in the three months before that.
The breakdown
- Mon66%(50 flights)
- Tue78%(49 flights)
- Wed74%(49 flights)
- Thu54%(52 flights)
- Fri80%(51 flights)
- Sat72%(50 flights)
- Sun65%(51 flights)
71%
May
Jun 70% → May 71% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 70% | 30 |
| July 2025 | 65% | 31 |
| August 2025 | 79% | 29 |
| September 2025 | 60% | 30 |
| October 2025 | 61% | 31 |
| November 2025 | 70% | 30 |
| December 2025 | 63% | 30 |
| January 2026 | 59% | 27 |
| February 2026 | 64% | 22 |
| March 2026 | 84% | 31 |
| April 2026 | 87% | 30 |
| May 2026 | 71% | 31 |
- Departures on time
- 66%
- Diverted
- 0%
- Flights flown
- 352
- Months covered
- 12
Same route, other flights
Keep nerding
Based on 359 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.