On Thursday night, the seventh day of the Hebrew month of Cheshvan, Jews living in Israel began praying for rain. From this date, Ashkenazi Jews will change the phrase, "And give blessing" to “And give dew and rain for a blessing,” (Ten Tal Umatar) to their weekday prayers, while Sephardi Jews say a completely different prayer including the request for "dew and showers".
Jews living abroad will begin saying the blessing for rain in several weeks' time.
Israel is facing a water shortage. While abundant rainfall in February brought the Kinneret back over its “red line” - the point at which water levels are dangerously low – the country is still recovering from five consecutive dry years.
The custom of adding the prayer for dew and rain on 7 Cheshvan dates back to the times of the First Temple and Second Temple. At that time, Jews would gather in Jerusalem and bring sacrificial offerings during the holiday of Sukkot.
When the holiday ended, the pilgrims would return home. It took those who lived farthest from Jerusalem 15 days to make the journey, so prayers for rain were delayed for 15 days, in order to avoid requesting rain at a time when it would make their travel difficult.
Prayers for rain will be recited until the Passover holiday in spring.