What is the proper saying that starts “If rain comes from the east …”?
We think you are referring to the adage “When the wind is from the east, ‘Tis neither good for man nor beast,” and there may be something to that theory. Generally, an east wind will precede rain. The validity of this saying is somewhat dependent on where you live. In the midwestern part of the United States, between the Rocky Mountains and the Appalachian Mountains, the only significant source of moisture is the Gulf of Mexico. Hence any wind with a southeasterly or southerly component can produce moisture from the Gulf of Mexico to well into the central part of the United States. Any wind from the west will be “descending” from the Rocky Mountains. Descending winds are warm and dry, so no moisture is brought in from the west. The Appalachians, which are substantially lower in elevation than the Rockies, do not present a significant a barrier and do allow moisture to cross from the East into the Midwest, so therein lies the problem.