There are three sources of the Jewish holidays.
The Torah commands the observance of five annual holidays: Rosh HaShanah, Yom Kippur, Sukkot, Pesach (Passover), and Shavuot. These are the most sacred of the Jewish holidays.
Many others come from Jewish tradition, such as Chanukah and Purim which commemorate significant events in the history of the Jews.
Four holidays were established by the Rabbinate of the State of Israel.
The observance of all of these holidays is according to the Hebrew calendar. The nature of this lunar calendar can cause the dates to vary by as much as one month on the Gregorian calendar. The holiday dates for the next few years can be found on the URJ Calendar of Jewish Holidays
THE CYCLE OF THE JEWISH YEAR -- AN INTRODUCTION by Rabbi David Kudan
The Jewish Ritual year begins with Rosh Hashana, the Religious New Year -- but we know that the seasons are cyclical. There is really no beginning or ending; all divisions of time are arbitrary and artificial. Yet our tradition recognizes that we need ending points and opportunities for new beginnings, times to wipe the slate clean -- as much as humanly possible, and to refocus on the future. Rosh HaShanah is actually only one of 4 New Years that Jews observe throughout the year!
What about the meaning of Yom Kippur, the "Day of Atonement." All religions must confront the problem of guilt -- human beings universally acquire a sense of regret for certain actions which have negative consequences, whether intended or not. How do we live with our mistakes? How do we ask forgiveness? Can a supernatural force assuage or soothe us? Judaism offers a human-centered approach to living with our mistakes, "sins" in traditional language, and moving behond.
What of Sukkot? It is an agricultural festival, -- a harvest festival, that brings us closer to the flow of nature. It is also a time to consider the fragility of our existence, and our impact on the natural world. It is a time to connect to the infinite as we focus on the intimate. The traditional reading for Sukkot is the book of Ecclesiastes -- A Time for Every Season -- a book that is imbued with a skeptical philosophical approach that sets aside complex theology and urges us to enjoy life -- within the confines of morality and basic humane values.
The fall season of observances concludes with Simhat Torah -- the celebration of the Torah. This represents yet another layer of tradition as we recommit ourselves to intellectual pursuits. It is not accidental that the celebration of the autumn harvest of learning coincides with the beginning of the academic year. It is a time to take joy in the life of the mind. Torah is not a book, but rather an ongoing conversation with those of all generations. It is a way of asking questions that go to the core of what it means to be human, and challenge us to raise human existence to a new level of ethical development, while seeking a measure of personal meaning in texts that we can apply our own lives.
The major Spring holidays of the Jewish calendar are Tu Bishvat, Purim, Passover, and Shavuot. There are some minor observances as well, and some modern additions to the calendar that many Jews observe as well – notably, Lag B'omer, Israel Independence Day, and Holocaust Memorial Day.
Stepping back from the particulars of each holiday, we can see an overarching theme of rebirth and hope that animates the observances.
Tu BiSh'vat is often referred to as "The New Year of the Trees." It is a spring holiday only in potential – as it occurs in the dead of Winter – in late January or early February, the 15th day of the month of Shevat. It is a time to think philosophically, even mystically about the nature of existence and our connections to the natural world. It has also become a time of celebration of the riches of the Environment, and a time to reaffirm our commitment to preserving and caring for the world that has been entrusted to us. What a perfect holiday for our age! As always, Judaism experiences the universal through the specific, the intimate relationship. In this instance the Jewish commitment to stewardship is expressed through a love of the Land of Israel. Planting trees in Israel has long been a favored Tu Bishvat activity.
Purim is a joyous holiday with a serious message – evil exists and cannot be eliminated. We are engaged in an endless struggle to contain it and to continue to look to the future with courage and optimism. On this holiday we read the Book of Esther and try to symbolically wipe out our enemies. The comic-book nature of the motivating story is emphasized by dressing up in costumes and trying to drown out the name of the arch-villain Haman whenever it is mentioned.
Passover is the most widely observed of all Jewish holidays. Based on the story of the Exodus it is the archetype of the possibility of liberation from all oppression whether in the political or personal sphere. The Seder meal is a joyous symposium for those of all ages to enact and explore a key chapter in our history and to draw lessons that will carry u forward in our lives. It is a celebration of survival and an epiphany of hope. No wonder that Passover was probably the original New Year in Biblical times.
Shavuot is observed Seven weeks after Passover and marks the time of the ripening and harvest of the barley crop in Israel. On top of that agricultural theme, the holiday has come to commemorate the giving of the Ten Commandments to the Jewish people. Adding yet another layer, it has become a time to reflect on the importance of choosing a Jewish way of life – whether through conversion or reaffirmation of one's Jewish identity. The Story of Ruth is the key text that is read on this festival: It is the story of a young widow, a woman of Moab who follows her mother-in-law Naomi and attaches herself to Naomi's people and her faith with deep sincerity.
As we observed in our discussion of the Fall holidays, we know that the seasons are cyclical. There is really no beginning or ending; all divisions of time are arbitrary and artificial. Yet our tradition recognizes that we need ending points and encouragement to start anew, to turn over a new leaf, even times to wipe the slate clean -- as much as humanly possible, and to refocus on the future. The Spring holidays afford us numerous opportunities to just that, to reflect on the past and to look towards new beginnings.