Proverbs 26:1

rain in harvest "For six months in the year no rain falls [in Palestine], and the harvests are gathered in without any of the anxiety with which we are so familiar lest the work be interrupted by unseasonable storms. In this respect at least the climate has remained unchanged since the time when Boaz slept by his heap of corn; and the sending thunder and rain in wheat harvest was a miracle which filled the people with fear and wonder (1 Samuel 12:16-18); and Solomon could speak of -rain in harvest" as the most forcible expression for conveying the idea of something utterly out of place and unnatural (Proverbs 26:1)." Smith's Dict. of Bible, Art. Rain.