Airport · ISP · Islip, New York
Islip, NY
Islip, NY posts bottom-quartile on-time performance among the 382 tracked U.S. airports, as a mid-size U.S. airport. According to the U.S. DOT Bureau of Transportation Statistics, drawn from 54,300 flights (2020–2025); its biggest delay driver is late aircraft.
Data updated 2026-06-13
- 77.9%
- On-time
- Top 92%
- on-time, US airports
- 71 min
- Delay when late
- 1.62%
- Cancelled
Key Performance Metrics
Total Flights
54,300
Best Month
Nov 92%
Worst Month
Jul 85.3%
Delayed
11,984
Cancelled
881
ISP on-time rate vs. the national average
Behind the U.S. average across all 382 tracked airports.
Where ISP sits among all 382 tracked airports
ISP's 77.9% on-time rate falls in the 75-80% band, the 48-airport band it shares.
National on-time-rate distribution
- 60-65% 1
1 airport between 60% and 65% on-time
1 airports
- 65-70% 4
4 airports between 65% and 70% on-time
4 airports
- 70-75% 9
9 airports between 70% and 75% on-time
9 airports
- 75-80% 48
48 airports between 75% and 80% on-time
48 airports
- 80-85%
192 airports between 80% and 85% on-time
192 airports
- 85-90%
116 airports between 85% and 90% on-time
116 airports
- 90-95% 12
12 airports between 90% and 95% on-time
12 airports
What this shows ISP is marked in the 75-80% band.
Delay Cause Breakdown
Top delay cause: Late Aircraft. Total delay minutes: 400,850.
ISP - seasonal on-time pattern
Best: November (92%) · worst: July (85.3%)
Seasonal Performance Patterns
Monthly averages across all years of data. Best month: November (92% on-time). Most delays: July (85.3% on-time).
| Month | Avg Flights | Avg Delayed | Avg Cancelled | On-Time % |
|---|---|---|---|---|
| December | 858 | 223 | 13 | 87% |
| November | 771 | 129 | 3 | 92% |
| October | 678 | 113 | 5 | 91.5% |
| September | 584 | 98 | 5 | 91.9% |
| August | 710 | 185 | 11 | 87.7% |
| July | 738 | 231 | 10 | 85.3% |
| June | 684 | 188 | 5 | 87.1% |
| May | 721 | 179 | 8 | 88.4% |
| April | 809 | 172 | 45 | 90% |
| March | 891 | 195 | 19 | 89.5% |
| February | 780 | 136 | 8 | 91.7% |
| January | 827 | 150 | 15 | 91.7% |
Year-Over-Year Performance
Annual flight volume and on-time trends at ISP.
ISP - on-time rate by year
2020–2025, year-over-year trend.
| Year | Flights | Delayed | Cancelled | On-Time % |
|---|---|---|---|---|
| 2025 | 10,569 | 1,231 | 54 | 88.4% |
| 2024 | 9,555 | 1,089 | 92 | 88.6% |
| 2023 | 9,399 | 1,078 | 75 | 88.5% |
| 2022 | 9,416 | 1,169 | 218 | 87.6% |
| 2021 | 8,713 | 935 | 101 | 89.3% |
| 2020 | 6,648 | 215 | 341 | 96.8% |
Cancellation & Diversion Analysis
Flight disruption statistics for Islip, NY.
Cancellation Rate
1.62%
881 of 54,300 flights
Diversion Rate
0.14%
75 of 54,300 flights
Delay Rate
22.1%
11,984 of 54,300 flights
Monthly Performance
Recent 24 months of flight data.
| Period | Flights | Dep Delayed | Arr Delayed | Cancelled | Diverted |
|---|---|---|---|---|---|
| Dec 2025 | 918 | 163 | 145 | 11 | 1 |
| Nov 2025 | 791 | 75 | 78 | 4 | 0 |
| Oct 2025 | 729 | 69 | 58 | 2 | 2 |
| Sep 2025 | 701 | 49 | 43 | 1 | 2 |
| Aug 2025 | 806 | 111 | 102 | 1 | 3 |
| Jul 2025 | 926 | 146 | 158 | 6 | 7 |
| Jun 2025 | 898 | 126 | 137 | 3 | 1 |
| May 2025 | 1,072 | 128 | 132 | 9 | 4 |
| Apr 2025 | 1,073 | 92 | 100 | 1 | 1 |
| Mar 2025 | 965 | 105 | 114 | 9 | 1 |
| Feb 2025 | 868 | 87 | 82 | 4 | 0 |
| Jan 2025 | 822 | 80 | 87 | 3 | 0 |
| Dec 2024 | 865 | 135 | 109 | 3 | 1 |
| Nov 2024 | 699 | 46 | 43 | 0 | 0 |
| Oct 2024 | 539 | 44 | 37 | 10 | 0 |
| Sep 2024 | 583 | 41 | 43 | 3 | 0 |
| Aug 2024 | 756 | 113 | 115 | 12 | 1 |
| Jul 2024 | 814 | 126 | 120 | 16 | 2 |
| Jun 2024 | 794 | 92 | 104 | 7 | 1 |
| May 2024 | 834 | 101 | 123 | 8 | 1 |
| Apr 2024 | 866 | 94 | 98 | 9 | 1 |
| Mar 2024 | 935 | 128 | 123 | 10 | 0 |
| Feb 2024 | 912 | 65 | 81 | 5 | 1 |
| Jan 2024 | 958 | 104 | 127 | 9 | 1 |
Top Routes from ISP
Busiest routes to and from Islip, NY.
| Route | Flights | On-Time | Distance |
|---|---|---|---|
| ISP (Islip) → MCO (Orlando) | 7,628 | 77.6% | 971 mi |
| MCO (Orlando) → ISP (Islip) | 7,608 | 75.7% | 971 mi |
| BWI (Baltimore) → ISP (Islip) | 7,398 | 76.7% | 220 mi |
| ISP (Islip) → BWI (Baltimore) | 7,390 | 88.3% | 220 mi |
| ISP (Islip) → PBI (West Palm Beach/Palm Beach) | 4,604 | 76.2% | 1,052 mi |
| PBI (West Palm Beach/Palm Beach) → ISP (Islip) | 4,599 | 76.2% | 1,052 mi |
| TPA (Tampa) → ISP (Islip) | 2,419 | 81.1% | 1,034 mi |
| ISP (Islip) → TPA (Tampa) | 2,416 | 73% | 1,034 mi |
| FLL (Fort Lauderdale) → ISP (Islip) | 1,202 | 74.4% | 1,092 mi |
| ISP (Islip) → FLL (Fort Lauderdale) | 1,139 | 78.1% | 1,092 mi |
Airports With a Similar On-Time Rate
Other U.S. airports nationwide whose on-time rate is closest to Islip, NY's 77.9%.
Other Airports in New York
Compare performance with other New York airports.
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Keep exploring
More flight data around Islip, NY.
New York flight data
Statewide on-time and delay aggregates, plus every reporting airport in New York.
View NY data →Airport rankings
See where ISP sits among U.S. airports on on-time rate and average delay.
Best on-time airports →Compare airports
Put ISP head-to-head with another airport on delays and reliability.
Open comparison tool →What the Data Says About ISP
Islip, NY in Islip, New York handled 54,300 flights in the Bureau of Transportation Statistics dataset between 2020 and 2025, posting a 77.9% on-time departure rate. Of those flights, 11,984 experienced delays, 881 were cancelled, and 75 were diverted. The cancellation rate works out to 1.62%, the diversion rate to 0.14%, and the average delay when departures run late is 71.0 minutes. These figures are the baseline for comparing ISP against other airports in the same state and nationally.
Breaking down what drives delays at ISP, Late Aircraft leads the pack. Late Aircraft accounts for 45.0% of total delay minutes, followed by Carrier at 26.4% and NAS (National Aviation System) at 25.5%. Weather contributes 3.0% of delay minutes at this airport, while security holds the smallest share at 0.1%. Travelers often overestimate the weather share; the BTS categorization shows late-arriving aircraft and carrier operations as the larger contributors.
Seasonally, November runs the cleanest at ISP with a 92% on-time rate, while July is the roughest at 85.3% - a 7-point swing between best and worst month. Volume peaks in March, when average flights hit 891. The busiest route connecting ISP is to MCO (Orlando), with 7,628 flights at a 77.6% on-time rate. Combine these numbers - 77.9% on-time, 71.0-minute average delay, 1.62% cancellation rate, and you have a concrete picture of departure reliability at Islip, NY.
Frequently Asked Questions
What is the on-time performance rate at Islip, NY (ISP)? ▼
What is the most common cause of delays at ISP? ▼
What is the average delay time at ISP? ▼
What is the best month to fly from ISP? ▼
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How many routes operate from ISP? ▼
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Flight Guides
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Using ISP's data
An airport-level on-time rate is a starting point, not a guarantee for your specific flight.
- Check the busiest route from ISP before you book a connection. See top routes
- Travel in November rather than July if your dates are flexible. Seasonal patterns
- Scores vary by airline and route within the same airport; check the specific carrier you're flying. Browse airlines
On-time rate reflects the BTS historical average across all reporting carriers at this airport, not any single flight or airline.
Related
Source: U.S. Bureau of Transportation Statistics (BTS) Airline on-time performance and operational reliability · 2025
Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. Airport figures are computed directly from BTS On-Time Performance data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.