Forgot to say Vesein Tal Umatar:
One who forgot to say Vesein Tal Umatar during the period that it is to be said [which is in Eretz Yisrael between the 7th of Marcheshven and Pesach, and in the Diaspora between the 5th/6th of December and Pesach] is required to repeat Shemoneh Esrei. The following is the ruling regarding one who remembered in middle of Shemoneh Esrei that it was not yet said:
Remembered prior to beginning Teka Beshofar: [If one remembered prior to saying Hashem’s name in Bareich Aleinu, then he is to say it in the place of remembrance.] If one remembered [after saying Hashem’s name in Bareich Aleinu, or after completing the blessing of Bareich Aleinu, but] prior to beginning [the first word of] Teka Beshofar, he is to say it there.
Remembered after beginning Teka Beshofar: If one only remembered after beginning the blessing of Teka Beshofar, prior to [finishing the blessing of] Shomeia Tefila, then he is not required to return [to Bareich Aleinu] and rather he is to say it in the blessing of Shomeia Tefila [prior to “Ki Ata Shomeia”].
Remembered after Shema Koleinu prior to beginning Ritzei: If one remembered after concluding the blessing of Shomeia Tefila, but prior to beginning Ritzei, then he is to say Vesein Tal Umatar [Livracha] and then [immediately] begin Ritzei.
Remembered after beginning Ritzei: If one only remembered after beginning Ritzei, then [if one remembered] prior to taking steps back at the conclusion of Shemoneh Esrei, then he is to return to Birchas Hashanim [i.e. Bareich Aleinu]. If he already [completed Shemoneh Esrei and] took three steps back, he must return to the beginning of Shemoneh Esrei. Furthermore, even if he did not yet take three steps back but has already recited the [second] verse of Yiyu Leratzon at the end of Shemoneh Esrei, he must return to the beginning.
Chart for one who remembered that he did not say Vesein Tal Umatar:
|Area of Shemoneh Esrei||The Law|
Prior to Hashem’s name in Bareich Aleinu
|Go back to the words Visein Tal Umatar|
Prior to Teka Beshofar
|Say it there|
Prior to Hashem’s name in Shema Koleinu
|Say it there|
After saying Ritzei
|Go back to back to Bareich Aleinu|
After saying 2nd Yehi Ratzon
|Repeat Shemoneh Esrei.|
If one is in doubt as to if he said Vesein Tal Umatar:
If one is in doubt as to whether he recited Veisein Tal Umatar, then if he is within the 30 days from when it was begun to be said [within 30 days after the 7th of Cheshvan in Israel, and within thirty days after the 5th of December in the Diaspora] we assume that he did not say it, and it thus follows the same law as one who omitted it. After the passing of thirty days, we assume that he said it, and hence he is not to go back and repeat it.
 Admur 117:5; Michaber 117:5; Brachos 29; See Piskeiy Teshuvos 117:6
 Admur 117:4; Michaber 117:4; Brachos 26b
 Admur ibid; M”A 117:5; Tur 114; Ravayah Taanis 846, brought in Rosh beginning of Taanis; Levush 117:6; Makor Chaim of Chavos Yair 117:4-5; Shaareiy teshuvah 117:5 in name of Elya Raba117:9; Noda Beyehuda 9; Machazik Bracha 117:2; P”M 117 M”Z3; Beir Heiytiv 117:8; Chayeh Adam ; Derech Hachaim; Birchas Habayis 40:36; Aruch Hashulchan 117:6; Kaf Hachaim 117:34 in name of Ben Ish Chaiy, Beis Oveid, Chesed Lealafim; Toras Chaim Sofer 117:10; See Piskeiy Teshuvos ibid footnote 49
Other opinions: Some Poskim rule that he is not to say it there, but rather wait to say it until Shema Koleinu. [M”B 117:15; Biur Halacha 114:6 “Belo” in name of Rishonim; Mamar Mordechai 117:9; Kitzur SHU”A 19:2; Shulchan Hatahor 117:6]
If one purposely skipped the saying of Visein Tal Umatar: If one intentionally skipped the saying of Visein Tal Umatar Livracha, despite knowing its Halachic requirement and remembering to say it, then some Poskim rule but he is required to repeat from the beginning of Shemoneh Esrei. [1st opinion in Admur 104:4; 114:9; M”A 104:6; Bach 10:6] Other Poskim, however, rule that it suffices for him to return to the beginning of the blessing. [2nd opinion in Admur 104:4; Taz 104:3; Olas Tamid 104:11] According to all, if you do not return right away to the beginning of the blessing and rather continued from the mistake, then he must return to the beginning of Shemoneh Esrei. [Admur ibid]
 See Piskeiy Teshuvos 117:6 that initially one is to go back to Visein Tal Umatar and continue from there, although if he did not do so, and simply said it in the area of remembrance, then it remains valid.
 Ashel Avraham Butchach 117; Orchos Chaim Spinka 117:4; Teshuvos Vehanhagos 2:58; Piskeiy Teshuvos 117:6
 See Admur 114:5
 The reason: As by saying it in this area it is considered as if he is saying it in Birchas Hashanim, as explained in 114:7. [Admur ibid] There it is explained that so long as one has not yet begun the next blessing the previous blessing is not considered to have been concluded regarding these additions that must be recited, and invalidate the prayer if omitted. However, regarding those additions that do not invalidate the prayer when omitted, the conclusion of the previous blessing ends that blessing even prior to beginning the next blessing, and hence one may no longer recite the non-invalidating additions once one has completed the blessing. [Admur 114:7]
 Admur ibid; Michaber ibid; Gemara ibid
 The reason: The reason that Visein Tal Umatar may be recited in Shema Koleinu, and not Mashiv Haruach, is because Mashiv Haruach is a praise of G-d and has no relation with Shomei Tefila [and therefore if it was not said according to Nussach Ashkenaz, then one must return to the beginning of Shemoneh Esrei, as stated in 114]. [Admur ibid; M”A 117:6; Beis Yosef 114; Tosafus Brachos 29a; Talmidei Rabbeinu Yona Brachos 19b]
What comes first, Visein Tal Umatar, Aneinu, personal prayers: Visein Tal Umatar is to be recited first before anything else, such as Aneinu on a fast day, [or personal prayers] being that it is more severe, as if it is not said at all one is required to repeat Shemoneh Esrei, and therefore it is proper to precede it. [Admur ibid; Rama 117:5; M”A 117:7; Abudarham]
 Admur ibid; Michaber 117:5
If one remembered after saying the words Baruch Ata Hashem: Some Poskim rule that he should conclude Lamdeini Chukecha, and then resume with Visein Tal Umatar and conclude Shomeia Tefila. [M”B 114:32] Other Poskim, however, rule that he is not to do so. See Piskeiy Teshuvos ibid and 114:9; Ketzos Hashulchan 47 footnote 7
 Kitzur SHU”A 117:6; Ben Ish Chaiy Beshalach 18; Kaf Hachaim 117:37; See Piskeiy Teshuvos ibid footnote 53
 The reason: As by saying it in this area it is considered as if he is saying it in Shomeia Tefila. [Admur ibid] As explained in the previous footnote.
 Admur ibid; Michaber ibid; Rambam Tefilla 10:9; Rosh Brachos 4:14
 The reason: As the saying of this verse represents a removal of his mind from saying any more supplications, and his prayer has concluded, as explained in M”A 422:2. [Admur ibid]
 Admur 114:10 regarding Mashiv Haruach and the same applies for Visein Tal Umatar Levracha [Kaf Hachaim 117:32]
 The reason: As until the pass of 30 days [90 prayers] of the recital of the new addition we assume one said the usual wording that he was accustomed to say until that point, unless he knows for certain that he recited the correct dialect. [ibid]
Reciting it 90x: Prior to the conclusion of the 30 days one is not to repeat the beginning of the blessing of Michayeh Meism until … Morid Hageshem for a total of 90x in order to make for oneself a status quo that he has now regulated himself to say it and hence no longer needs to go back in case of doubt, as there are opinions which argue on this ruling and hence one ends up entering himself into a dispute if he does not remember if he said it prior to the 30 days concluding. [Admur 114:11]
 If he did not Daven some of the days within the 30 days: The above law applies even if there were a few days in-between in which he did not say it, such as he did not Daven at all, his Chazaka is not weakened, being that he said it for majority of the days. [Admur ibid]