Boston, MA

What the Data Says About BOS

Boston, MA in Boston, Massachusetts handled 1,455,478 flights in the Bureau of Transportation Statistics dataset between 2020 and 2025, posting a 79.9% on-time departure rate. Of those flights, 292,211 experienced delays, 17,391 were cancelled, and 1,913 were diverted. The cancellation rate works out to 1.19%, the diversion rate to 0.13%, and the average delay when departures run late is 78.3 minutes. These figures are the baseline for comparing BOS against other airports in the same state and nationally.

Breaking down what drives delays at BOS, Carrier leads the pack. Carrier accounts for 37.1% of total delay minutes, followed by Late Aircraft at 34.4% and NAS (National Aviation System) at 25.0%. Weather contributes 3.4% 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 BOS with a 92.8% on-time rate, while July is the roughest at 88% — a 5-point swing between best and worst month. Volume peaks in March, when average flights hit 21,852. The busiest route from BOS is to DCA (Washington), with 49,205 flights at a 81.6% on-time rate. Combine these numbers — 79.9% on-time, 78.3-minute average delay, 1.19% cancellation rate — and you have a concrete picture of departure reliability at Boston, MA.