Halachos of משיב הרוח
משיב הרוח ומוריד הגשם
12. In Mussaf of the last day of Sukkos, we begin saying משיב הרוח ומוריד הגשם in the second brachah of Shemoneh Esrei, and we continue to say it until Mussaf of the first day of Pesach (שו"ע או"ח סי' קי"ד ס"א ).
13. Some say ומוריד הגָשֶם , with a komatz under the gimel (שו"ת אג"מ או"ח ח"ד סי' מ' ושו"ת אבן ישראל ח"ח סי"ט ), but the earlier version was ומוריד הגֶשֶם , with a segol under the gimel (חיד"א יוסף אומץ, ליקוטי מהרי"ח ).
Mistakes Regarding משיב הרוח
14. Said ‘Morid Hatal’. If, in the winter, one said מוריד הטל, which he was used to saying in the summer [nusach Sephard], and he realized his mistake during the brachah, he should rectify it by mentioning geshem (ביה"ל שם ד"ה אין). If he remembered after “ונאמן אתה,” he must repeat “ונאמן אתה” to make the words before the chasimah similar to the chasimah (מ"ב סקכ"ט ). If he already said “ברוך אתה ה',” he should continue davening since we need dew even in the winter.
15. Didn’t say anything. However, if he did not even say מוריד הטל [this often happens to those who daven nusach Ashkenaz and do not say it in the summer] and already finished the brachah, he may say משיב הרוח if he did not yet start אתה קדוש or נקדש. If he already started אתה קדוש or נקדש, he must start Shemoneh Esrei again (שו"ע סי' קי"ד ס"ה, ומ"ב). He does not need to say ד' שפתי תפתח again (מ"ב סקכ"א) or ברוך שם כבוד מלכותו לע ולם ועד since his tefillah was a tefillah, albeit missing a part.
Unsure If He Said משיב הרוח
16. If one is unsure whether he said משיב הרוח and it is within thirty days [21 Cheshvan] or 90 tefillos after starting to say it, whichever comes first (מ"ב סקל"ז ), he is assumed to have omitted it since he is still not used to saying it. If he is at a point in the tefillah which necessitates repeating it, he must repeat it. [A set shliach tzibbur has an advantage since he says each tefillah twice and gets to 90 sooner (שע"ת)].
17. If after thirty days one finds himself making this mistake three times, he loses his chazakah and it is as if he is within thirty days unless he always corrects himself right away (א"א בוטשאטש ).
18. If right before or during Shemoneh Esrei one was aware that he had to say the proper addition, then even if he became unsure right after Shemoneh Esrei, we assume he said the right one. However, if he became unsure within Shemoneh Esrei, near the relevant brachah, it is likely he made a mistake, and if necessary, he must repeat Shemoneh Esrei (מו"ק). If he did not remember before or during Shemoneh Esrei to add the proper words, even if he remembered after Shemoneh Esrei, he must daven again.
19. One who knows he is the type of person who is always unsure if he said the right thing should only pay attention to doubts that arise right away, not to doubts that arise after some time.
Southern Hemisphere
20. The poskim discuss what Jews living in the Southern Hemisphere, e.g., South Africa, South America, or Australia, whose summer coincides with our winter, should say in their tefillah. Originally, some held that all they should do is ask for what they need in Shema Koleinu (שו"ת תורת חיים ח"ג סי' ג').
Please do not read during davening or Krias HaTorah
21. Subsequently, many poskim ruled they should daven like the rest of the world since rain is not harmful to them in their summer. Nowadays that rain can be utilized even during the summer, most poskim agree they should daven like the rest of the world. Thus, during these days, they too say משיב הרוח ומוריד הגשם (שו"ת מנח"י ח"ו סי' קע"א, תשובות והנהגות ח"א סי' צ"ח).
