Another matter, “I will give your rains at their time” – on Wednesdays.13This is before the heavy market days at the end of the week, when people are purchasing their food for Shabbat. Rain on the heavy market days would be inconvenient for people. Do you say on Wednesdays, or is it even on Fridays? They said: Even if the years are like the years of Elijah,14During those years there was a severe drought. and rain falls on Fridays, it is nothing other than a cursed omen. How, then, do I realize: “I will give your rains at their time”? It is on Wednesdays.
Why God Sends Rain on the Perfect Day for Shabbat Shopping
Vayikra Rabbah 35:9