Best time to fly out of Long Island MacArthur (ISP)
The early-flight folk wisdom holds up at Long Island MacArthur: departures in the 6–8am band left on time 92.8% of the time, against 60.1% in the 2–4pm band. These are historical odds, not forecasts. The records say what happened on this schedule over three years; they know nothing about tomorrow’s thunderstorm.
Data through June 2026 · Bureau of Transportation Statistics
On-time rate by hour and day
On this page, “on time” means a departure that pushed back less than 15 minutes behind its scheduled time — the Bureau of Transportation Statistics definition, and the one airlines are held to.
| Departure time | Mon | Tue | Wed | Thu | Fri | Sat | Sun |
|---|---|---|---|---|---|---|---|
| Before 6am | 87 | – | – | 95 | 91 | 95 | 91 |
| 6–8am | 93 | 91 | 94 | 94 | 92 | 91 | 94 |
| 8–10am | 87 | 89 | 86 | 89 | 88 | 83 | 86 |
| 10am–12pm | 84 | 87 | 84 | 86 | 85 | 82 | 83 |
| 12–2pm | 71 | 75 | 78 | 76 | 71 | 75 | 67 |
| 2–4pm | 54 | 69 | 59 | 54 | 61 | 64 | 59 |
| 4–6pm | 71 | 71 | 68 | 64 | 65 | 68 | 63 |
| 6–8pm | 64 | 70 | 69 | 61 | 59 | 60 | 55 |
| 8–10pm | – | – | – | 66 | 65 | – | 58 |
| 10pm–12am | – | – | – | – | – | – | – |
The steadiest stretch at ISP was 6–8am — 92.8% of departures left on time across 2,434 flights. The weakest was 2–4pm at 60.1%. 6–8am departures from ISP left on time 92.8% of the time across 2,434 flights; 6–8pm departures, 61.5% across 1,184. That is a gap of 31.3 points, and it is the whole case for the early flight.
The year at ISP
July was the hard month at ISP: 65% of departures left on time, across 1,247 flights. October was the easy one at 84.1%. Each month pools three years of that month, so a single bad week does not decide it.
| Month | Share departures that left on time | Flights |
|---|---|---|
| January | 78.3% | 1,325 |
| February | 79.3% | 1,323 |
| March | 72.7% | 1,363 |
| April | 79.5% | 1,431 |
| May | 78% | 1,346 |
| June | 75.2% | 1,261 |
| July | 65% | 1,247 |
| August | 71.7% | 1,162 |
| September | 82.8% | 976 |
| October | 84.1% | 1,039 |
| November | 84.1% | 1,206 |
| December | 69.1% | 1,420 |
Airlines at ISP
Every airline with at least 100 departures from ISP, busiest first. These are that airline’s departures from this airport only — its record across the country sits on its own page.
| Airline | Left on time | Typical delay | Cancelled | Departures |
|---|---|---|---|---|
| Southwest Airlines | 77.7% | 59 min | 1% | 8,619 |
| Frontier Airlines | 73.1% | 91 min | 3.2% | 4,378 |
| JetBlue Airways | 77.9% | 86 min | 1.8% | 2,102 |
What delays out of ISP were put down to
Airlines file a reason with every arrival running 15 minutes late or more. Across 3,353 flights that departed ISP and ran 15 minutes late or more, the delay minutes break down with 45.8% put down to late-arriving aircraft and 27.2% to airline operations.
- Late-arriving aircraft 45.8%
- Airline operations 27.2%
- Air traffic & airport volume 23.9%
- Severe weather 3.1%
- Security 0.1%
Late-arriving aircraft is the knock-on category: the plane came in late, so it went out late again. It is why a 7am problem in Newark is still a problem in Denver at dinnertime, and why it is usually the biggest slice on the bar.
If you are connecting through ISP
Of 15,103 scheduled arrivals into ISP, 74.2% reached the gate less than 15 minutes behind schedule. Of the 3,615 arrivals that ran late, 55.4% were no more than 45 minutes behind — which is the difference between a tight connection and a new boarding pass.
Work out a specific layover — pick the airport and the minutes you have, and the tool reads the same arrival records back as a share.
Busiest routes out of ISP
Ranked by flights, with the share that arrived on time at the far end. Where a route carries enough flights for a page of its own the chip goes there; otherwise it goes to the destination airport.
- MCO 74.9% on time · 4,257 flights
- BWI 85.7% on time · 3,855 flights
- PBI 74.7% on time · 3,288 flights
- TPA 72.6% on time · 1,550 flights
- FLL 73% on time · 1,036 flights
- MYR 78.8% on time · 401 flights
- RSW 71.5% on time · 366 flights
- MIA 78.1% on time · 245 flights
- ATL Not enough flights to say · 44 flights
- RDU Not enough flights to say · 38 flights
ISP in one number
Long Island MacArthur (ISP)
Rank 141 of 363 US airports by departures. Steadiest stretch of the day: 6–8am. Hardest month: July.
Questions about ISP
- What is the best time of day to fly out of Long Island MacArthur?
- 6–8am. Departures in that band left on time 92.8% of the time across 2,434 flights, July 2023 through June 2026 — the best of the ten bands in the day. The 2–4pm band was the weakest at 60.1%.
- Is the early flight out of ISP really more reliable?
- 6–8am departures from ISP left on time 92.8% of the time across 2,434 flights; 6–8pm departures, 61.5% across 1,184. That is a gap of 31.3 points, and it is the whole case for the early flight.
- What is the worst month to fly out of ISP?
- July: 65% of the departures that flew left on time, with 1,247 scheduled. October was the other end of the year at 84.1%. Each figure pools three years of that calendar month.
- Which airline is most on time at ISP?
- JetBlue Airways — 77.9% of its 2,102 departures from ISP left on time. Frontier Airlines sat at the other end at 73.1% over 4,378 flights. Only airlines with at least 100 departures here are ranked.
- How often are flights cancelled at ISP?
- 1.7% of scheduled departures were cancelled over July 2023 through June 2026. Cancellations are counted against everything scheduled, not against everything that flew — a rate that looks small still adds up to real people in a rebooking line.