[16] According to Ginat Veradim, a Kohen who is not fasting may nonetheless perform Birkat Kohanim at Minĥa of a fast day in congregations that recite Birkat Kohanim, because there is no concern that he will perform the blessing while drunk on a fast day. All other poskim disagree. According to Ĥazon Ish, oĥ 20, Kohanim may perform the mitzva even when praying an early Minĥa, as there is no concern that they will be drunk. However, most poskim maintain that Birkat Kohanim is recited only when praying Minĥa at the time of Ne’ila, which is close to shki’a. Rav Pe’alim oĥ 5, Kaf Ha-ĥayim 129:7, Lu’aĥ Eretz Yisrael (by R. Yeĥiel Michel Tikochinsky), Piskei Teshuvot 129:1 all maintain this view. The basis for this opinion is the fact that the Kohanim do not bless the people at Minĥa of Yom Kippur, as the Sages were concerned that they might mistakenly do so on a regular day. The reason they were concerned is that Minĥa can be prayed on Yom Kippur at the same time we pray Minĥa on a regular day. Furthermore, the earliest time for Minĥa is close to midday, which is when people eat lunch and are liable to drink wine, as opposed to Ne’ila, which is said at the end of the day. Therefore, on a day that has no Ne’ila service, the Kohanim bless the people during Minĥa in congregations that recite Birkat Kohanim only if it is said at the time of Ne’ila. Nonetheless, everyone agrees that if the Kohanim ascended the platform to perform the mitzva during a Minĥa service that is being held before plag ha-minĥa, they may continue. Many authorities rule this way with regard to Minĥa of Yom Kippur. Plag ha-minĥa is 1.25 seasonal hours before the end of the day. There is a dispute whether “the end of the day” refers to shki’a or tzeit ha-kokhavim; see Peninei Halakha: Prayer, ch. 24 n. 9. For our purposes here, we calculate plag from shki’a, as explained there, ch. 20, n. 3. Le-khatĥila, it is best to schedule Minĥa such that the congregation will recite the Amida half an hour before shki’a, as this is the proper time, le-khatĥila, for Ne’ila.

Be-di’avad, if the ĥazan’s repetition of the Amida extends past shki’a, the Kohanim may perform the mitzva up until tzeit ha-kokhavim, as there is a combination of uncertainties here: 1) According to Raavya, Yere’im, and Or Zaru’a, Kohanim may perform the blessing at night; 2) the status of bein ha-shmashot is uncertain, and it may be considered daytime; 3) according to Rabbeinu Tam, the period following shki’a is definitely daytime. sah 623:8 and Piskei Teshuvot 623:13, quoting R. Shlomo Zalman Auerbach and R. Yosef Shalom Elyashiv, both rule accordingly. Yeĥaveh Da’at 6:40 and Or Le-Tziyon 2:8:13 concur, adding that this period lasts for 13.5 minutes following shki’a.