Most people when discussing the tekufot align them with directly with the astronomical solstices or equinoxes, but according to the Jewish Encyclopedia they may actually fall up to 14 days after this. For example, think about the fact that the Winter solstice is called the “Tekufat Tevet.” This year (5771 / 2010) the Winter Solstice actually falls in the month of Tevet, but this is not always the case.
Many years, the Winter Solstice actually appears in the month of Kislev, and aligns with closely with Hanukkah, which occurs during the dark moon nearest the winter solstice. If you look at the Gregorian calendar for 2000-2009, only five of those ten years had the Winter solstice falling in Tevet. Want to see for yourself? 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009) So on the years when the Winter Solstice falls in Kislev, when do you you celebrate Tekufat Tevet? I say we celebrate the solstice on the solstice. It’s an astrological event, not a subjective one.
“The winter solstice seems to have to do with sight, or the lack thereof. Mountains become visible to Noah, and the patterns of nature become visible to Adam and Eve. Leviathan is associated with inner site. Jepthah, on the other hand, is blind to his own wrong doings. On the winter solstice the sun’s light begins to become stronger, and we too consider how to strengthen our vision.” (From the Jewish Book of Days by RK’Jill Hammer)
There are actually many Jewish winter solstice tales and a great deal of lore around the Winter and other tekufot. For a variety of reasons, we’re not supposed to drink water stored in the house or in “vessels” on the first day of the tekufot. The belief is that the water is poisoned with blood. Each season seems to have its own reason for this. At the Winter Solstice it’s because that is the day Jepthah sacrificed his daughter.