That's the period between Samhain and Imbolc. That calendar is based on the amount of light. Samhain (Halloween) is the dey halfway between the autumn equinox a

That's the period between Samhain and Imbolc. That calendar is based on the amount of light. Samhain (Halloween) is the dey halfway between the autumn equinox and the winter solstice, and Imbolc is the day halfway between the winter solstice and the spring equinox. In those days the amount of light available was a huge issue and feast days were marked around the days the light shifted, as well as shifts in behaviour. For example the harvest work would traditionally begin the day afer Samhain, halfway between the summer solstice (Midsummer) and the autumn equinox.