Schevat / שבט is the fifth month after the " bourgeois " Jewish calendar and the eleventh month after the " religious " calendar. He always takes 30 days. According to the Gregorian calendar Schevat begins in mid- January.
The term " Schevat " comes from the Akkadian and means tribe or rod. In the Tanakh the month name is shown once occupied:
"In the four and twentieth day of the eleventh month - the month of Shevat is - in the second year of King Darius the word of the LORD unto Zechariah, the son of Berechiah, the son of Iddo, the prophet "
According to Jewish tradition falls in the month Schevat the New Year of the Trees. In the opinion of the House of Shammai, it falls on the 1st of Shevat, in the opinion of Hillel House on the 15th of the month (see Mishnah Rosh Hashanah 1:1). The latter opinion has become tradition determining.