i have lived and surfed in New England for 54 years. A nor’easter in Summer time is rare as hen’s teeth. Like any other weather phenomenon, there are always outliers and anomalies. But my first hand, long term experience can verify that any difference in the consistency of surf up here in summer is not due to nor’easters. Late May through August are typically dead flat. What we do get, with any regularity, is short period windswell from the southwest. Nantucket probably has the most consistent surf in summer, by virtue of its position downwind from the SW fetch/swell window.