V'sen Tal: Why December 4th?

Though both the mention of rain and request for rain are inserted in the winter, there is a difference between them. Mention of rain (mashiv haruach) is inserted during the rainy season, and the request for rain (v’sen tal u’matar l’bracha) is made at that time when we desire rainfall. We begin mentioning rain (mashiv haruach) on Shmini Atzeres. Though it would make sense to mention rain during the Succot festival (as that is the beginning of the raining season), we nonetheless refrain from doing so. This is because rain is considered a bad omen during the festival since it makes it impossible to fulfill the commandment of sitting in the succah. Therefore, the sages ruled that our praise for rain begin after the Succot festival (Shemini Atzeres). What is more, they decided that this would take place during the Mussaf prayer when all are present and it is possible to make an announcement reminding everybody to begin mentioning rain. The evening prayer was not chosen because not everybody attends it; the morning prayer was likewise ruled out because it is impossible to make an announcement before it, for it is forbidden to interrupt between the Shema (geulah) and the Amida (tefilla) (Beit Yosef, Shulchan Arukh, Orach Chaim 112:1, 2). However, the sages delayed the request for rain fifteen days (v’sen tal), to the night of the seventh of Cheshvan. They did this in order that the last of the festival pilgrims be able reach home before the rains fall (Gemara Ta’anis 10a). This custom continues even after the destruction of the Holy Temple because any custom which recalls the great days when the Holy Temple stood is very dear to us, and we do not wish to discontinue it. Only after the Temple is rebuilt (speedily in our days!) will the Sanhedrin be able to change the time for requesting rain taking into account modern means of transportation. In Babylon, the sages ruled that the request for rain should be delayed for sixty days after the Autumnal Equinox. This was because they had plenty of water from the Tigris and Euphrates Rivers and therefore did not need to make numerous requests for rain with the onset of the rainy season. According to the Shulchan Aruch all other lands outside of Israel (America) follow the practice of Babylon and begin requesting rain on the sixtieth day after the Autumnal Equinox However, we must ask the obvious question, the autumnal equinox is September 22nd, sixty days later is November 22nd, so how did we arrive at the custom to begin the recitation of v’sen tal on December 4th? The answer to this question requires a historical background. In the year 46 BCE, Julius Caesar established what became known as the Julian Calendar. This calendar had 12 months, and one year had 365.25 days. Every four years, the quarter-days appeared on the calendar as a leap year day. However, the actual length of a solar year is slightly less than this, approximately 365.24219 days. In the short run, this difference is negligible, but over time it adds up ( you end up a day behind approximately every 150 years). This eventually caused a problem with regard to the seasons, which depended on the solar year and were gradually failing to fall out at the proper time. To fix this situation, Pope Gregory XIII, in 1582, instituted the Gregorian calendar. Two changes were made with the change in calendar. The first is that 10 days were "lost," meaning that October 4th that year was followed by October 15th (which makes sense as approximately 1500 years had passed, they were 10 days behind). With regard to our issue, v'sein tal u'matar that year was said on December 1st instead of November 22nd. The second change that was made was more subtle, but is perhaps more important. The rule for leap years was altered slightly, with every century year NOT divisible by 400 losing its leap-year status. Thus, 1600 was a leap year, but 1700, 1800, and 1900 were not. This had the effect of changing the average length of a year to 365.2425 days, a difference that is much less noticeable over time (a margin of error of roughly 3 days in 10,000 years). As a result, the date for v'tein tal u'matar was bumped up one day in each of those three years (1700, 1800 and 1900) ( We didn’t bump up in 2000 because that is divisible by 4 and thus was a leap year), bringing us to our current date of December 4th (thus, after 2100, the date will become December 5th). The only exception to be aware of is that v'tein tal u'matar is added beginning from December 5th in the Diaspora when the following Gregorian year is a leap year. This is due to the fact that the Jewish year begins several months earlier and factors in the extra day from the beginning (This relates to the fact that the Jewish calendar is based on both the solar and the lunar ones). In southern hemisphere countries, such as Argentina, Brazil, and Australia, where the rainy season coincides with Israel’s summer, Torah authorities rule that the request for rain be made in the "Birkat Hashanim" blessing according to the custom of the Land of Israel. This is because the Land of Israel is the focal point of creation and all other lands are subordinate to her. However, if in these southern hemisphere countries there are places where rain causes damage in the summer, it is impossible for the people there to request rain in "Birkat Hashanim." They should therefore recite the summer version all year round, and request rain in the "Shomeah Tefillah" blessing. The reason that they are not able to request rain in "Birkat Hashanim" during their rainy season is that they must follow the practice of the Land of Israel. And they cannot request rain in "Birkat Hashanim" during Israel’s rainy season because rain is deleterious for them at this time. Therefore, they request rain for themselves during their rainy season in the "Shomeah Tefillah" blessing. Furthermore, it is a good idea for people in these places to request rain for Israel during Israel’s rainy season in the "Shomeah Tefillah" blessing. What it amounts to, then, is that they recite the summer version of "Birkat Hashanim" all year round, and in "Shomeah Tefillah" they request rain in their rainy season for themselves and rain in Israel’s rainy season for the Land of Israel. (compiled with help from chaburas.org)