Pagan Book of Days for May 15th
Maia and Mercury/Vesta/Cold Sophie/Idea of May/Goddess month of Maia end/Egyptian Day
Today is sacred to the month goddess Maia and her son Mercury, and also to Vesta, goddess of the hearth and eternal fires. On the Idea of May, the vestal virgins, the ancient Roman priestesses of Vesta, performed a rite intended to regulate the water supply for the coming summer. In southern Germany this is the day of Cold Sophie, when extra-cold weather is expected and needs to be counteracted by appeals to the goddess of fire and warmth.
Source
The Pagan Book of Days
Nigel Pennick
Witches Of The Craft® 