Portsmouth, NH

What the Data Says About PSM

Portsmouth, NH in Portsmouth, New Hampshire handled 4,468 flights in the Bureau of Transportation Statistics dataset between 2020 and 2025, posting a 80.6% on-time departure rate. Of those flights, 865 experienced delays, 59 were cancelled, and 4 were diverted. The cancellation rate works out to 1.32%, the diversion rate to 0.09%, and the average delay when departures run late is 81.2 minutes. These figures are the baseline for comparing PSM against other airports in the same state and nationally.

Breaking down what drives delays at PSM, Late Aircraft leads the pack. Late Aircraft accounts for 40.0% of total delay minutes, followed by Carrier at 28.3% and NAS (National Aviation System) at 23.5%. Weather contributes 8.1% of delay minutes at this airport, while security holds the smallest share at 0.0%. Travelers often overestimate the weather share; the BTS categorization shows late-arriving aircraft and carrier operations as the larger contributors.

Seasonally, February runs the cleanest at PSM with a 91.6% on-time rate, while June is the roughest at 81.5% — a 10-point swing between best and worst month. Volume peaks in April, when average flights hit 106. Combine these numbers — 80.6% on-time, 81.2-minute average delay, 1.32% cancellation rate — and you have a concrete picture of departure reliability at Portsmouth, NH.