Yule
Yule is the Winter Solstice, the longest night of the year. Traditionally, this night is honored by keeping vigil throughout the long cold night and then celebrating the return of the Sun at dawn.
Samhain is another cross-quarter day, falling between the autumnal equinox (Mabon) and the winter solstice (Yule). In my personal practice, I celebrate the Sabbat on its true day, saving October 31 for the Halloween festivities.
Imbolc
Imbolc is a cross quarter day, between the Winter Solstice (Yule) and the Spring Equinox (Ostara). Imbolc is a festival of light, a time of preparation for the coming season, a gestation period for the plans and dreams that we will manifest in the coming months.
Mabon marks the autumnal equinox, and is the point where nighttime begins growing longer than day. This is the beginning of the dark half of the year. Energy slowly shifts direction, ebbing inward.
The second of the three fertility festivals, Ostara arrives on the Spring Equinox. This sabbat is a celebration of rebirth, renewal, and the fertility of Mother Earth.
Lughnassadh is another cross-quarter day, falling between the summer solstice (Midsummer) and the autumn equinox (Mabon). It is known as the “Harvest of the Grain” because this is the time when the first of the summer crops are ready to be brought in from the fields.
Beltane, the last of the three fertility festivals, is all about fire, passion, and fertilization. Many people celebrate this sabbat on April 31st (May Eve), but traditionally, Beltane is a cross-quarter day, occurring exactly between Ostara (the spring equinox), and Litha (the summer solstice).
The Summer Solstice, the longest day of the year.
The sun is at his most powerful. Mother Earth is in full pregnancy, and fertility rites abound. Celebrations and rituals usually involve large bonfires, and spells for manifestation are extremely effective.