Basing itself on the deep and mysterious connection between the source of our individual lives and the source of the life of the planet, Druidry recognizes eight particular times during the yearly cycle which are significant and which are marked by special observances.
Of the eight times, four are solar and four are lunar - creating thereby a balanced scheme of interlocking masculine and feminine observances. At the Solstices, the Sun is revered at the point of its apparent death at midwinter - and of its maximum power at the noon of the year when the days are longest. At the Equinoxes, day and night are balanced.
These four festivals are astronomical observances, and we can be sure our ancestors marked them with ritual because many of the stone circles are oriented to their points of sunrise or sunset. By the time the circles were built, our ancestors had become a pastoral people, and times of sowing and reaping were vital to them.
But as well as these four astronomical, solar festivals, there exist four times in the year which were and are also considered sacred. The two sets of festivals represent far more than just times which our ancestors chose to honor the plant and animal life-cycles though. They demonstrate our thorough interconnected-ness with both the animal and plant realms.
Solar Festivals — Spring equinox, Summer solstice, Autumn equinox, Winter solstice
Lunar Festivals — Imbolc, Beltane, Lughnasadh, Samhain
The Lunar festivals are also called "Fire" Festivals. All of the fire festivals are celebrated at night and are held during the Full Moon. They are primarily concerned with agriculture, nature, pasturing and livestock.
~Shyloh, edited by Supply and Foxfire
See Also: Druid Festivals, Wheel of the Celtic Year