Lunar Synodical Period and Widespread Precipitation

Science. 1962 Sep 7;137(3532):748-9. doi: 10.1126/science.137.3532.748.

Abstract

Precipitation activity over broad areas appears to be closely associated with the monthly lunisolar cycle. Indexes of precipitation in the continental United States over a continuous 50-year period, and 91-year daily histories of individual stations, reveal that heavy rains occur most frequently in the first and third weeks of the synodical month.