Zman for Maariv
Chachamim, Rebbi Yehuda
7. The Mishna says that the end of the zman for Mincha is the beginning of the zman for Maariv, only there is a machlokes Tannaim when that is. The halacha in this machlokes is not conclusively determined, as will be explained.
8. Chachamim. The Chachamim hold the zman for Mincha is until the night. They are machmir to only daven while it is definitely day, i.e., until bein hashemashos. The zman for Maariv begins at true tzeis hakochavim.
9. Rebbi Yehuda. Rebbi Yehuda holds the zman for Mincha is until plag hamincha, which is halfway between mincha ketana and the end of the day. Right after plag, one may daven Maariv, and of course repeat Krias Shema after tzeis to fulfill the mitzva of Krias Shema in its proper time, at night (below, 11).
10. Plag hamincha. Some poskim say plag is 1/1 halachic hours before shekiya, with the twelve hours of the day starting at neitz and ending at shekiya (לדעת הגר''א א''ח סי' תנ''ט ). Others hold it is 1/1 halachic hours before tzeis, with the twelve hours starting at alos and ending at tzeis (סתימת השו''ע סי' רל''ג, וסי' תמ''ג ).
11. Krias Shema after tzeis. It should be noted that this whole discussion is only about the tefilla of Maariv, which is d’rabanan. However, one must be sure to say Krias Shema – which is d’oraisa – in its zman, after tzeis, each person according to his opinion: either the Geonim’s tzeis or Rabbeinu Tam’s tzeis. Thus, if one davened Maariv before tzeis, he must repeat Krias Shema without the brachos after tzeis (שו''ע סי' רל''ה ס''א ).
