A weekly feature of Torah Tidbits to help clarify practical and conceptual aspects of the Jewish Calendar, thereby better fulfilling the mitzva of HaChodesh HaZeh Lachem...
Aside from being a month, Tevet is also one of the four T'kufot, seasons, of the year - T'kufat Tishrei (officially, the beginning of the fall - autumnal equinox), Tevet (winter solstice), Nisan (vernal equinox), and Tamuz (summer solstice). Actually, the T'kufot do not match up well with the seasons' beginnings because we use an admittedly inaccurate (albeit Tradition- al) calculation for the T'kufot. Known as the T'kufot of Shmuel, it considers the length of a solar year to be 365¼ days, which was the basis of the Julian calendar, rather than the more accurate calculations of Rav Adda. The only practical use of the T'kufot are the beginning of Tal U'Matar season in Chutz LaAretz (60 days after T'kufat Tishrei), and the once in 28 years Birkat HaChama, on T'kufat Nisan (next one coming IY"H Wed. April 8th, 2009).