Mabon occurs sometime between September 20 and 23. The astrological sign Libra begins on this day. Like Ostara, the day and night are of equal length. At this time, the season of harvest is coming to a conclusion as the earth begins to prepare for winter.

In most traditions, the god's funeral continues. In a few, he is still preparing for his death. Mythologically, this is when Persephone must return to the underworld. Demeter, saddened by this, brings winter to the land until her daughter returns at Ostara. The day is named after Mabon, who was born on the equinox, then kidnapped from his mother Modron when he was only three days old.

Mabon is also known as Harvest Home. Traditional activities include honoring fruit (formerly harvested in September) and gathering with family and friends for a witches' Thanksgiving feast. It is a time to give thanks for the abundance of the past year. The color of the sabbat is brown. Yarrow, wheat, apples, amber, acorns, and pomegranates are all appropriate altar decorations and offerings. Animals associated with Mabon include the owl and the stag. In place of Mabon, the legend of Demeter and Persephone can be retold or Dionysus can be invited. Cerridwen is sometimes called the barley goddess, and the god Frey is associated with the harvest.