During the winter months, we recite in the second blessing of the Amida prayer "Mashib Ha’ru’ah U’morid Ha’geshem" in place of "Morid Ha’tal," which is recited in the summer months. The Shulhan Aruch writes that if one mistakenly recited "Morid Ha’tal" in place of "Mashib Ha’ru’ah," he has nevertheless fulfilled his obligation, and does not need to repeat the Amida. If, however, one recited neither "Mashib Ha’ru’ah" nor "Morid Ha’tal," then he has not fulfilled his obligation and must therefore repeat the Amida.
The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909), in Parashat Beshalah (Shana Rishona, 16), addresses the case of someone who realized immediately after completing the second blessing of the Amida – meaning, after he recited "Mehayeh Ha’metim" – that he mistakenly recited "Morid Ha’tal" instead of "Mashib Ha’ru’ah." If the person had not yet begun the next blessing ("Ata Kadosh"), the Ben Ish Hai writes, then he should recite "Mashib Ha’ru’ah" at that point, and then continue with "Ata Kadosh." In the view of the Ben Ish Hai, as long as one has not yet begun the next Beracha, he is still considered to be involved in the second Beracha, such that he can still recite "Mashib Ha’ru’ah."
Hacham Ovadia Yosef, however, both in Yabia Omer (1:22:13) and in Halichot Olam (Beshalah, 5), disputes this ruling. He contends that since mistakenly reciting "Morid Ha’tal" instead of "Mashib Ha’ru’ah" does not invalidate one’s recitation of the Amida, correcting this mistake does not justify making an interruption in between two blessings of the Amida. In a case where one made a mistake which would invalidate the Amida, Hacham Ovadia concedes, then one would, in fact, insert the required recitation in between two Berachot. And thus Hacham Ovadia writes that if one recited neither "Mashib Ha’ru’ah" nor "Morid Ha’tal" in the second blessing, such that he would have to repeat the Amida, then if he realized his mistake immediately after concluding "Mehayeh Ha’metim," before beginning "Ata Kadosh," he should recite "Mashib Ha’ru’ah" at that point. In this case, his Amida would otherwise be invalid, and so making an interruption in between the two Berachot to recite "Mashib Ha’ru’ah" is justified. If, however, one recited "Morid Ha’tal," then since this mistake does not invalidate the Amida, he should not interrupt in between two Berachot of the Amida to correct this mistake.
Summary: If, during the winter months, one mistakenly recited "Morid Ha’tal" instead of "Mashib Ha’ru’ah," then he does not need to repeat the Amida. If, however, one recited neither "Mashib Ha’ru’ah" nor "Morid Ha’tal," then he must repeat the Amida. If one mistakenly recited "Morid Ha’tal" instead of "Mashib Ha’ru’ah," and he realized his mistake immediately after reciting "Mehayeh Ha’metim," before beginning "Ata Kadosh," he should simply continue the Amida. If, however, one recited neither "Mashib Ha’ru’ah" nor "Morid Ha’tal," and he realized his mistake immediately after reciting "Mehayeh Ha’metim," then he should recite "Mashib Ha’ru’ah" at that point and then continue with "Ata Kadosh."
