Nantucket, MA

What the Data Says About ACK

Nantucket, MA in Nantucket, Massachusetts handled 17,080 flights in the Bureau of Transportation Statistics dataset between 2020 and 2025, posting a 80.5% on-time departure rate. Of those flights, 3,324 experienced delays, 426 were cancelled, and 22 were diverted. The cancellation rate works out to 2.49%, the diversion rate to 0.13%, and the average delay when departures run late is 91.1 minutes. These figures are the baseline for comparing ACK against other airports in the same state and nationally.

Breaking down what drives delays at ACK, Late Aircraft leads the pack. Late Aircraft accounts for 47.9% of total delay minutes, followed by NAS (National Aviation System) at 26.9% and Carrier at 22.1%. Weather contributes 2.9% of delay minutes at this airport, while security holds the smallest share at 0.2%. Travelers often overestimate the weather share; the BTS categorization shows late-arriving aircraft and carrier operations as the larger contributors.

Seasonally, January runs the cleanest at ACK with a 100% on-time rate, while July is the roughest at 87.1% — a 13-point swing between best and worst month. Volume peaks in July, when average flights hit 814. The busiest route from ACK is to JFK (New York), with 2,109 flights at a 76.2% on-time rate. Combine these numbers — 80.5% on-time, 91.1-minute average delay, 2.49% cancellation rate — and you have a concrete picture of departure reliability at Nantucket, MA.