The Amida Prayer during the Summer Months
The first day of Pesach marks the end of the rainy season and as such, beginning from the Mussaf prayer of this day, “Mashiv Ha’Ruach U’Morid Ha’Geshem” is no longer mentioned in the Amida prayer. Instead, we say: “Ata Gibor Le’Olam Hashem Mechaye Metim Ata Rav Le’Hoshia Morid Ha’Tal.” There are some Ashkenazi communities who do not mention “Morid Ha’Tal” at all in the “Mechaye Ha’Metim” blessing.
Similarly, beginning from the Arvit prayer following the first day of Pesach (outside of Israel, the Arvit prayer following the second day of Pesach), “Ve’Ten Tal U’Matar” is no longer recited in the Blessing of the Years; rather, only “Ve’Ten Beracha” is recited. The Sephardic custom is to recite a much longer version of the Blessing of the Years beginning with “Barech Aleinu” during the winter months. During the summer months, this is substituted with the “Barechenu” text.
One who Mistakenly Recites “Mashiv Ha’Ruach”
Since rainfall during the summer months is an ominous sign, our Sages teach us (Rosh Hashanah 3b) that if one mistakenly recites “Mashiv Ha’Ruach U’Morid Ha’Geshem” during the summer months, he must repeat his prayer.
However, not every situation of mistakenly reciting “Mashiv Ha’Ruach U’Morid Ha’Geshem” warrants repeating the entire Amida prayer. This all depends on when one becomes aware of his mistake.
If one remembers that he has recited “Mashiv Ha’Ruach U’Morid Ha’Geshem” before finishing the blessing, i.e. before reciting the words “Baruch Ata Hashem Mechaye Ha’Metim,” one should return to the beginning of the blessing (“Ata Gibor”) and recite “Morid Ha’Tal” in the proper place.
If one only becomes aware of his mistake after reciting “Baruch Ata Hashem,” one should end off by reciting the words “Lamedeni Chukecha” (in order for his blessing not to be in vain) and then return to the beginning of the blessing. However, if one only remembers his mistake after concluding the blessing with the words “Mechaye Ha’Metim,” one must begin the Amida prayer anew.
One who Mistakenly Recites “Ve’Ten Tal U’Matar Livracha”
If one mistakenly recited “Ve’Ten Tal U’Matar Livracha” in the Blessing of the Years during the summer months, one must recite the Amida prayer over again. However, this also depends on where one became aware of his error.
If one remembers before concluding the blessing by reciting the words “Mevarech Ha’Shanim,” one should return to the beginning of the blessing and recite the correct version. If one remembers after reciting the words “Baruch Ata Hashem,” one should recite “Lamedeni Chukecha” and then proceed to return to the beginning of the Blessing of the Years.
If one remembers only after he has concluded this blessing, in the middle of any other blessing which follows, or even in the middle of “Elokai Netzor,” one must return to the beginning of the Blessing of the Years and correct his error. Following this, one should continue the rest of the Amida prayer as usual.
However, if one only becomes aware of his mistake after reciting the “Yihyu Le’Ratzon” verse at the conclusion of the Amida prayer (the one following “Elokai Netzor”), one must return to the beginning of the Amida prayer and recite it once again. (See Shulchan Aruch, Orach Chaim, Chapter 117 and commentaries ibid.)
