A weekly cycle of precipitation in the Eastern Mediterranean

Abstract Analysis of a homogenized dataset from 60 in-situ weather stations across Israel over the past 70 years revealed a significant weekly cycle in precipitation. Generally, weekends exhibit lower precipitation levels, aligning with reduced anthropogenic activity. At some stations, precipitation on a particular weekday was twice that of another day. In addition, for many stations, the day of maximum rainfall shifted during the period studied. We rule out the influence of natural variability by comparing the data with output from a model simulation that lacks a weekly anthropogenic cycle and conducting a shuffled days test. Interestingly, a marginally significant weekly cycle is also evident in this region’s SLP pressure, which, if not a result of random factors, suggests a connection to the local cycle in aerosols and rainfall. That would then raise the question of whether aerosol variations drive the precipitation cycle and pressure anomalies or whether the pressure anomalies drive the rainfall cycles, indicating the need for further research.