The saying of “v’ten tal u’matar livracha” was instituted by the Rabbis based on the precipitation needs of the major Jewish communities of the time. According to our minhag, the entire Diaspora follows the Babylonian practice of praying for rain beginning from the day they calculated to be sixty days into Tekufat Tishrei (the autumn season). The Rosh[1] felt that areas with different rainfall requirements should not follow the Babylonian practice. In those countries that need rain at other periods of the year, one should be able to add “v’ten tal u’matar livracha” as appropriate. The Shulchan Aruch[2] agrees with the Rosh in principle but not in practice, out of deference to minhag. He therefore concludes that someone in a locality that, like Israel, needs the rainy season to begin earlier should nonetheless not begin praying for rain. If he did so, however, it is not certain whether he must repeat Shemoneh Esrei like someone who prayed for rain when inappropriate. Thus, he should repeat Shemoneh Esrei with the intention that it count as a tefillat nedava (voluntary prayer). The Rama[3] does not require repeating Shemoneh Esrei.
The Mishna Berura[4] cites two opinions on whether a ben Eretz Yisrael (one who resides in Israel) visiting abroad should follow the schedule of Israel (7 Cheshvan) or of the place where he is currently (December 5). The rationale to follow Israel’s schedule is more convincing if he will benefit from the rain, which hopefully will fall during this period, either because his family is there[5] or especially if he plans to return home during that year.[6]
Because of the doubt that surrounds this matter, major poskim[7] suggest the following simple solution: It is permitted to ask for rain in chutz la’aretz during the summer in the beracha of Shomei’a Tefilla, and it is sufficient b’di’eved to do so during the winter (useful for one who forgot to say “v’ten tal u’matar livracha” in its regular place). Thus, if a resident of Israel who is abroad says “v’ten tal u’matar livracha” in Shomei’a Tefilla (rather than in its usual beracha) during this intervening period (between 7 Cheshvan and December 5), he is safe according to all opinions.
Rav Feinstein,[8] on the other hand, implies that these people should recite “v’ten tal u’matar livracha” in its regular place. This is because the Shulchan Aruch really agrees with the aforementioned Rosh and rules against him only because of the minhag. Since there is no clear minhag regarding travelers, a ben Eretz Yisrael can say “v’ten tal u’matar livracha” in its usual place after 7 Cheshvan in a country where rain is desirable at that time of the year. Nevertheless, the former opinion is the safer one, especially for Sephardim.[9]
One who began saying “v’ten tal u’matar livracha” in Israel and left with plans to return should continue to insert it in his tefilla,[10] at the very least in Shomei’a Tefilla.[11] According to most authorities, a ben Eretz Yisrael in chutz la’aretz at this time may serve as chazan. He should follow his accepted practice in his silent Shemoneh Esrei but should omit “v’ten tal u’matar livracha” during chazarat hashatz.[12]