An excerpt from Patricia Monaghan's Season of the Witch

From winter, one can remember spring, summer, fall, can see all their patterns This is the time when all seems clear.
And all seems complete. There is not yet a call to begin again, for beginnings will come soon enough. This is the fallow time. This is the time of rest.
This is also the time of visions. For as the world sleeps, as the woman's energies withdraw into a coiled serpent at the base of her spine, the inner eye widens. There is so much to see beyond the world of appearances! Wisdom bestows its miraculous kaleidoscope. Spirits call from beyond time. What had been a glass wall between mind and world dissolves into a shimmering veil that blows open--often, then more often--to reveal new powers.
There is magic in all seasons, but winter's magic is most concise, most dense, most crystalline. It is diamond magic, cool and brilliant, not the fiery magic of coal. It is laser fineness, precise direction.