How reliable is Long Island Mac Arthur Airport?
Flights from ISP departed within 15 minutes of schedule in 77% of 30,427 flights in official BTS history — and weather is calmest in Aug. Here’s the full picture before you book.
Reliability score
on-time, cancellations & delays
Weather favorability
year-round climate
Origin-airport operations
What the departure punctuality at ISP looks like
On-time departures
across 30,427 flights
Source: BTS Airport Operations · data through 2026-06-25. Role-specific BTS departure history; advisory context, not a guarantee for any flight.
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Weather by month
When the weather works for you at Islip
A calm-weather score (0–100) for each month from decades of airport observations — how often conditions disrupt flying, not temperature. Higher is calmer.
Calmest month
Calmest flying weather of the year · 94/100 favorability
Roughest month
Most disruptive — low visibility & fog, snow · 80/100 favorability
The read on ISP
What the numbers say about flying through Long Island Mac Arthur Airport
Across official performance history, flights from Islip left within 15 minutes of schedule about 77% of the time over 30,427 flights. That's a respectable but unspectacular operational record. Pair it with a moderate cancellation rate of 2.3%. When a departure does run late, the typical delay is around 15 minutes.
On weather, Islip is an unusually calm-weather airport year-round. August is the calmest stretch for flying, scoring 94 out of 100 for favorable conditions, while February is the most disruptive at 80, driven mainly by low visibility & fog and snow. The year is relatively steady, so no single month stands out as one to avoid on weather alone.
None of this guarantees your specific flight — it’s the backdrop. To turn it into a booking, score real flights to Islip, read how we weigh it all in how the PlaneSane Score works, and brush up with how to pick a reliable flight and avoiding weather delays.
Common questions about ISP
- How reliable is Long Island Mac Arthur Airport (ISP)?
- Flights from Islip left within 15 minutes of schedule roughly 77% of the time across 30,427 flights of official history — a respectable but unspectacular operational record. The cancellation rate runs about 2.3%. It's advisory context, not a guarantee for any single flight.
- What is the best month to fly from ISP for good weather?
- August has the calmest flying weather at Long Island Mac Arthur Airport. February is the most disruptive, mainly from low visibility & fog and snow.
Planning a trip through Islip?
Score real flights to and from ISP on reliability, weather, and connection safety — not just price.