Sources and Reasoning:
1). Maran the Shulchan Aruch writes (Yoreh De’ah, siman 197, סעיף 4): Where there is duress, such as one who is afraid to immerse at night because of the cold, fear of robbers, or the like, she may immerse during the day on the eighth day. However, on the seventh day she may not immerse during the day, even where there is duress. Accordingly, the same applies in our case. Only on the eighth day would it be permitted to immerse during the day in a situation of concern or fear, but not during the seventh day. Especially since the Shach (se’if katan 11), in the name of many Rishonim, writes that if she immersed during the day on the seventh day, she must immerse again.
2). Nevertheless, there is room to say that on the seventh day, when she returns home in the evening and her husband is not at home, it may be permitted. Although the Shach [se’if katan 6] writes as follows: “It appears that even if she immerses close to nightfall and comes home after dark, it is forbidden, in accordance with the view of the Rashbam and those who follow him, regarding whom the poskim wrote that it is proper to be stringent. The Bach writes that even going from her home to the place of immersion during the day is forbidden. This refers to a case where the woman washes and combs her hair at home and goes to the immersion site. But where the bathhouse and the immersion site are in one place, and a woman goes during the day to the bathhouse an hour or two before nightfall and comes home after dark, even if the bathhouse and immersion site are close to her home, there is no concern of setting a precedent for her daughter, for the daughter knows that she remains at the bathhouse for washing and hair-combing and does not immerse until after dark,” end quote [Bach]. However, the Agur writes that the custom in Ashkenaz was to immerse close to nightfall, end quote. It is possible that he follows Rabbeinu Tam and those who follow him, who permit immersing close to nightfall provided that she comes home after dark; and it seems to me that this is indeed the practice. Nevertheless, one should be stringent. However, it appears that this applies specifically on the eighth day, when the prohibition is solely because of the concern of setting a precedent for her daughter, and in such a case Rabbeinu Tam is lenient close to nightfall. But on the seventh day, one may not immerse at all close to nightfall, and those who do so should be rebuked,” end quote.
The Sidrei Taharah (se’if katan 9) writes that the Shach follows the Tur [page 175], who writes that the dispute between Rabbeinu Tam and the Rashbam concerns the eighth day. However, Tosafot in this tractate (67b, s.v. mishum) makes clear that even on the seventh day Rabbeinu Tam permits immersion close to nightfall, since there is no longer any concern that she may come to a doubtful situation. This was already noted in the responsa Avodat HaGershuni (siman 20) and in Chacham Tzvi (siman 11).
Although the responsa Chut HaShani (siman 82) discusses at length and strains to justify the custom practiced in several holy communities, where, when a woman’s immersion night falls on Friday night, they immerse while it is still day, and in some communities they immerse during bein hashmashot—such was also the practice in Frankfurt—and then go home at night. The Be’er Sheva had already addressed this in his responsa, folio 89b [siman 73, 111a], and strongly protested this custom, writing that it should be opposed and abolished. See there, where he concludes: “But in a place where there is no custom, let this custom and others like it not be mentioned; rather, one must follow the ruling of the Shulchan Aruch, siman 197, and not depart from its words,” end quote, responsa Chut HaShani. So too writes the Minchat Yaakov [Torat HaShelamim, se’if katan 9], and likewise the Tzemach Tzedek, siman 66: Even if there are other residents in her home besides her own household, and she is embarrassed before them, and therefore wishes to immerse while it is still day in order to hasten her return home before the Shabbat meal so that they will not notice her—even so, she does not act properly, and those who do so should be protested and rebuked. So too writes the Solet LaMinchah [Torat HaShelamim there], that the Gaon Maharshal of Prague, of blessed memory, strongly protested women who did this.
However, the Sidrei Taharah (ibid.) writes that according to the above-mentioned reasoning of Rabbeinu Tam, one may find justification for those who immerse during bein hashmashot and come home after dark, if they do so so that the other residents of their home will not notice them. The responsa Igrot Moshe—Feinstein, vol. III (siman 60), also permits this in pressing circumstances, and assembles several leniencies there to permit it even when her husband is at home.
However, since virtually all the Acharonim write that this should not be practiced, it should not be permitted even in pressing circumstances. This is also the custom in Eretz Yisrael: not to permit it even when she returns home and her husband is not at home.
Especially during this war, there are unfortunately many missiles during the day as well. Moreover, if you go out for other purposes, as you wrote, there is no reason why she should not go out for the sake of a mitzvah. “One who is engaged in a mitzvah will know no evil.” If she is concerned, you should accompany her to the immersion site.
3). However, for Sephardim, one may be lenient to immerse on Friday afternoon during bein hashmashot, since in any event this is practiced every Friday afternoon because of immersion in warm water, and because no decree concerning shevut applies during bein hashmashot. The leading sages of Jerusalem also testified to this custom, among them in Taharat HaBayit, vol. II (pp. 452 and 464–467). This is likewise written in the responsa Or LeTzion, vol. II (chapter 35, letter 3).
This response was translated automatically from Hebrew and has not yet been reviewed by a person. Therefore, it may contain inaccuracies and should not be considered a definitive reference.
