Wiccans celebrate each full moon, as the moon is the symbol of the Goddess. These celebrations take place 12-13 times a year usually involving a rite worshipping the Goddess.
 
 

Sabbats recognize the changing of the seasons. Four of these days are determined by the Solstices and Equanoxes the astrinomical beginning of the seasons. While the other four days are associated with agriculture and the bearing cycles of animals.
 

Samhain-October 31 On this day we revere the loved ones that have passed on to the other life. This also marks the symbolic death of the God.

Yule-Dec.21 (or close to it) Celebrates the rebirth of the God through the Goddess.

Imbolc-Feb.1-2 This is when the wiccans celebrate the recovery of the Goddess from giving birth to the God. It is a festival of purification and reverence for renewing the fertility of the earth.

Ostara-March 21 The Spring Soltice, marks the first day of true spring. It is the time of the awakening of the earth. The sun grows in warmth and power.

Beltane-April 30 This is the festival that celebrates the young Gods venture into manhood. He and the Goddess join and and produce the bounty of nature.

Midsummer-June 21 This is the point where the powers of nature are at thier peak. Wiccans will gather to celebrate and to practice magick.

Lughnasadh-August 1, This is the beginning of the harvest. The God weakens as the first grains and fruit are cut. This is a ritual of Thanksgiving.

Mabon-September 21 This is the second harvest. The God prepares to leave his life behind him  as the fruits are gathered to nourish the people on earth. The warmth is weaker each day.

Samhain follows Mabon and the circle continues...................!