In Greek mythology, the Hyades (/ˈhaɪ.ədiːz/; Ancient Greek: Ὑάδες, popularly "the rainy ones", but probably from Greek hys, i.e. "swine") are a sisterhood of nymphs that bring rain.
The Hyades were daughters of Atlas (by either Pleione or Aethra, one of the Oceanides) and sisters of Hyas in most tellings, although one version gives their parents as Hyas and Boeotia. The Hyades are sisters to the Pleiades and the Hesperides.
The main myth concerning them is envisioned to account for their collective name and to provide an etiology for their weepy raininess: Hyas was killed in a hunting accident and the Hyades wept from their grief. They were changed into a cluster of stars, the Hyades, set in the head of Taurus.
Their number varies from three in the earliest sources to fifteen in the late ones. The names are also variable, according to the mythographer, and include:
Servius gives a set of five names that doesn't match any other known list: Pytho, Synecho, Baccho, Cardie, Niseis.
Additionally, Thyone and Prodice were supposed to be daughters of Hyas by Aethra, and have been added to the group of stars.
The Greeks believed that the heliacal rising and setting of the Hyades star cluster were always attended with rain, hence the association of the Hyades (sisters of Hyas) and the Hyades (daughters of ocean) with the constellation of the Hyades (rainy ones).
The Hyades are also thought to have been the tutors of Dionysus, in some tellings of the latter's infancy, and as such are equated with the Nysiads, the nymphs who are also believed to have cared for Dionysus, as well as with other reputed nurses of the god — the Lamides, the Dodonides and the nymphs of Naxos. Some sources relate that they were subject to aging, but Dionysus, to express his gratitude for having raised him, asked Medea to restore their youth.
In Tennyson's poem, Ulysses recalls his travels of old:
"I cannot rest from travel: I will drink - Life to the lees: All times I have enjoy'd - Greatly, have suffer'd greatly, both with those - That loved me, and alone, on shore, and when - Thro' scudding drifts the rainy Hyades - Vext the dim sea ..."