Hebrew Folk Proverbs on Rainfall Tested with 75 Years of Israeli Data

A recent study available on arXiv examines two Hebrew weather proverbs that connect lunar calendar anchor days to winter rainfall in Israel. The first saying asserts, "If Rosh Chodesh is rainy, the entire month will be rainy," while the second, derived from Hasidic tradition, claims, "If it rains on Shabbat Mevarechim, the whole month will be rainy." Shabbat Mevarechim occurs the last Saturday before each new Hebrew month, one to seven days before Rosh Chodesh. Researchers evaluated 75 years of daily rainfall data (1950–2024) from seven cities in Israel, encompassing 191,758 station-days and 2,422 observations of Hebrew months during the winter season (Marcheshvan–Adar). A rainy Rosh Chodesh raises the likelihood of a rainy month from 22.2% to 38.6% (an increase of 16.4 percentage points; chi-square = 57.8), marking the first formal examination of these proverbs, which reflect centuries of agricultural insight.