Tevet 5775 began last night at sundown, on the evening of December 21, 2014.
Despite its fancy beginning, Tevet is a quiet little month for Jews. The biggest things to happen in it are not Jewish days at all: Christmas and the Gregorian New Year (January 1) usually fall in the month of Tevet.
The only other official Jewish day of observance in this month is Asara b’Tevet [10th of Tevet] on which some Jews fast to remember the day in 588 BCE when the army of Nebuchadnezzar, emperor of Babylon, laid seige to Jerusalem. In the month of Av, a year and a half later, they would enter the city and destroy Solomon’s Temple, which we refer to as the First Temple.
One of the quirks of the Jewish calendar as we know it today is that it is in some ways a hand-me-down from ancient Babylon. Before the destruction of the first Temple by the Babylonians and the subsequent exile, we know that Jews followed a lunar calendar that began its months on the new moon and that had adjustments to keep the agricultural holidays in their proper seasons. We have a few month names from that calendar in the Torah, but most of the months seem to have been like modern Hebrew days. They went by number, “In the First Month” etc.
But the names of the months we use today came back from Babylon with our ancestors. Tevet in Babylon was Tebetu or something similar. If you are curious about the Babylonian calendar there are a few Internet sites that explore it, including this one.
Enjoy the last remaining nights of Chanukah and don’t forget to add the greeting, Chodesh Tov! Happy New Month!