Islip (ISP) to West Palm Beach/Palm Beach (PBI): On-Time Performance
Data through May 2026
When you fly ISP to PBI matters as much as anything else about the booking: the route swung from 93% on-time in November 2024 to just 57% in December 2025. Across the full period the route averages 73% on-time against a national 78%. Morning departures also hold up better than evening ones (86% vs 68%), which matters most in the rough months.
- On-time
- 73%
- arrived <15 min late
- Avg delay
- 21 min
- completed flights
- Cancelled
- 1.6%
- Flights/day
- 3.4
- last 12 months
- Duration
- 2h 57m
- scheduled
- Distance
- 1,052 mi
Best airline from ISP to PBI
3 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| Southwest Airlinesmost reliable | 75% | 17 min | 1.3% | 1,344 |
| Frontier Airlines | 74% | 26 min | 2.2% | 276 |
| JetBlue Airways | 70% | 26 min | 1.9% | 694 |
Monthly on-time trend
Best time to fly from ISP to PBI
Aim for departures around 7 a.m. (93% on-time); avoid 3 p.m. departures (58%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 75% | 22 min |
| Tuesdaybest | 76% | 18 min |
| Wednesday | 74% | 16 min |
| Thursday | 70% | 26 min |
| Friday | 74% | 21 min |
| Saturday | 75% | 20 min |
| Sunday | 70% | 22 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft42%
- Airline operations31%
- National airspace system24%
- Weather3%
Frequently asked questions
- How often are flights from ISP to PBI delayed?
- 27% of ISP–PBI flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 21 minutes.
- Which airline is most reliable from ISP to PBI?
- Southwest Airlines has the best on-time record on this route at 75%, based on 1,344 flights. 3 airlines flew ISP–PBI frequently enough to compare in this period.
- What is the best time of day to fly from ISP to PBI?
- Departures around 7 a.m. have the best record (93% on-time), while departures around 3 p.m. have the worst (58%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from ISP to PBI?
- The scheduled ISP–PBI flight time averages 2h 57m over 1,052 miles. Actual arrival times vary — flights on this route land 15+ minutes late 27% of the time.
- How often are ISP to PBI flights cancelled?
- 1.6% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
- What is the worst month to fly from ISP to PBI?
- December 2025 was the roughest month in this dataset, with only 57% of arrivals on time. The best was November 2024 at 93%. If your dates are flexible, that 36-point gap is worth planning around.
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Based on 2,314 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.