Question:
I have heard that one should not blow Shofar within the first three hours of Rosh Hashanah day, which is prior to Sof Zeman Kerias Shema. Is this accurate and does this apply only when praying without a Minyan, or should the Shofar ideally not be blown during the first three hours even with a Minyan?
Answer:
The letter of the law is that this concern applies specifically to one who is blowing Shofar without a Minyan. In such a case, one should delay the blowing until after three halachic hours have passed from the beginning of the day, which is after Sof Zeman Kerias Shema. The reason is that during the first three hours, Hashem judges according to strict justice, and there is concern that one’s prayers and shofar blasts may invoke heavenly scrutiny. After three hours have passed, the judgment of the world is tempered with greater mercy.
Nevertheless, some Poskim write that even when one is davening with a Minyan, it is proper to avoid blowing the Shofar within the first three hours of the day. Accordingly, many communities have the practical custom of scheduling the Shofar blowing later in the morning, after three hours have elapsed.
It should be noted, however, that this stringency should not be applied when it may cause someone to miss the mitzvah altogether. Accordingly, when blowing Shofar for unaffiliated Jews, hospital patients, homebound individuals, or anyone who may not otherwise hear the Shofar, one should blow for them whenever the opportunity presents itself, even within the first three hours of the day. In such circumstances, ensuring that a Jew fulfills the mitzvah of Shofar takes precedence over this preference.
Conclusion:
If one is praying without a Minyan, he should not blow Shofar within the first three hours of the day. Even with a Minyan, some Poskim rule that it is proper to avoid blowing the Shofar during this time, and many communities are accustomed to do so.
Sources:
Admur 591:14; Magen Avraham 591:9; Mishnah Berurah 591:15; Kaf Hachaim 591:36. Machazik Berachah 588:1; Mateh Efraim 588:2; Kaf Hachaim 588:6