Now You Know!

We begin saying "Mashiv HaRuach U'Morid HaGeshem" at Mussaf of Shmini Atzeres. The Gemara explains that we would not want to begin saying it on Sukkos itself, as rain during the holiday is a sign of Hashem's displeasure.

Customs vary. Some places announce "Mashiv HaRuach!" before Mussaf, so people would begin to say it in their silent Shemona Esrai. Other places do not announce it and the tzibbur doesn't begin to say it until Mincha, after Tefilas Geshem has been recited publicly.

One who is davening alone does not recite Tefilas Geshem nor is there an announcement.

If one is praying after the Tzibbur has presumably said Geshem he cannot omit Mashiv HaRuach, though very early, before the Tzibbur has said Geshem, he might not have to say it. The best practice, therefore, would seem to be, to say "Morid HaTal" in one's Shemona Esrai so he has fulfilled both opinions.

The Netziv, in Harchev Davar, says that on Sukkos, all the nations of the world would gather in Jerusalem to celebrate the festival and pray for the rains.

They did this in the days of Dovid and Shlomo and will do so again when Moshiach is here. The nations were also there when Shlomo spoke his words of Koheles, and it is for this reason that the name of G-d, "Elokim," is used exclusively in it, for they do not know more of Him.

Only Klal Yisrael merits knowing G-d's name of mercy, His attribute of "Hashem."