Sonnstill

Sonnstill, or Sun Still is the common name for the Summer Solstice, so named because the sun seems to sit still on the horizon on this, the longest day of the year. It is an important date for farmers, sailors, wizards, and pilgrims; in short, for anyone dependent on the cycles of the sun and those keeping track of the remaining days of the year.

Fertility rites are extremely common on this day, with young couples adorning themselves with flowers in their hair and dancing and drinking to songs dedicated to Taal and Rhya. The mysterious Elves are sometimes seen giving thanks and honour to their own Gods on this day. Children born on Sun Still are considered blessed and are thought to become bright, energetic adults destined for great things.

Source

 * Warhammer Fantasy RPG 2nd ED -- Tome of Salvation pg. 145